Organometallic compound, organic light-emitting device including the same, and diagnostic composition including the same

ABSTRACT

An organometallic compound represented by Formula 1: 
     
       
         
         
             
             
         
       
         
         
           
             wherein, in Formula 1, groups and variables are the same as described in the specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Applications No.10-2018-0001851, filed on Jan. 5, 2018, and No. 10-2019-0000390, filedon Jan. 2, 2019, in the Korean Intellectual Property Office, and all thebenefits accruing therefrom under 35 U.S.C. § 119, the content of whichis incorporated herein in its entirety by reference.

BACKGROUND 1. Field

The present disclosure relates to an organometallic compound, an organiclight-emitting device including the same, and a diagnostic compositionincluding the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, whichhave improved characteristics in terms of a viewing angle, a responsetime, brightness, a driving voltage, and a response speed, and whichproduce full-color images.

In an example, an organic light-emitting device includes an anode, acathode, and an organic layer disposed between the anode and thecathode, wherein the organic layer includes an emission layer. A holetransport region may be disposed between the anode and the emissionlayer, and an electron transport region may be disposed between theemission layer and the cathode. Holes provided from the anode may movetoward the emission layer through the hole transport region, andelectrons provided from the cathode may move toward the emission layerthrough the electron transport region. The holes and the electronsrecombine in the emission layer to produce excitons. These excitonstransition from an excited state to a ground state, thereby generatinglight.

Meanwhile, luminescent compounds, for example, phosphorescent compounds,may be used for monitoring, sensing, and detecting biological materialssuch as various cells and proteins.

Various types of organic light emitting devices are known. However,there still remains a need in OLEDs having low driving voltage, highefficiency, high brightness, and long lifespan.

SUMMARY

Provided are an organometallic compound, an organic light-emittingdevice including the organometallic compound, and a diagnosticcomposition including the organometallic compound.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to an aspect of an embodiment, an organometallic compound isrepresented by Formula 1:

In Formula 1,

-   -   M may be beryllium (Be), magnesium (Mg), aluminum (Al), calcium        (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu),        zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr),        ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag),        rhenium (Re), platinum (Pt), or gold (Au),    -   X₁ may be a chemical bond, O, S, N(R′), P(R′), B(R′), C(R′)(R″)        or Si(R′)(R″), and when X₁ is a chemical bond, Y₁ may be        directly bonded to M,    -   X₂ to X₄ may each independently be N or C, two selected from X₂        to X₄ may each be N, and the other may be C,    -   a bond between X₁ or Y₁ and M may be a covalent bond, one bond        selected from a bond between X₂ and M, a bond between X₃ and M,        and a bond between X₄ and M may be a covalent bond, and the        remaining two bonds may be coordinate bonds,    -   Y₁ and Y₃ to Y₅ may each independently be C or N,    -   among pairs of X₂ and Y₃, X₂ and Y₄, Y₄ and Y₅, X₅₁ and Y₃, and        X₅₁ and Y₅, the components in each pair may be linked via a        chemical bond,    -   ring CY₁ to ring CY₅ may each independently be selected from a        C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, and        each of ring CY₁, ring CY₃, and ring CY₄ may not be a        benzimidazole group,    -   a cyclometalated ring formed by ring CY₅, ring CY₂, ring CY₃,        and M may be a 6-membered ring,    -   X₅₁ may be selected from O, S, N-[(L₇)_(b7)-(R₇)_(c7)],        C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═O), N, C(R₇), Si(R₇), and        Ge(R₇),    -   R₇ and R₈ may optionally be linked via a single bond, a double        bond, or a first linking group to form a C₅-C₃₀ carbocyclic        group unsubstituted or substituted with at least one R_(10a) or        a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at        least one R_(10a),    -   T₁ and T₂ may each independently be a single bond, a double        bond, *—N(R₉)—*′, *—B(R₉)—*′, *—P(R₉)—*′, *—C(R₉)(R₁₀)—*′,        *—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—S—*′, *—Se—*′, *—O—*′,        *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₉)═*′, *═C(R₉)—*′,        *—C(R₉)═C(R₁₀)—*′, *—C(═S)—*′, or * C≡C—*′,    -   L₁ to L₄ and L₇ may each independently be selected from a single        bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group,        and a substituted or unsubstituted C₁-C₃₀ heterocyclic group,    -   b1 to b4 and b7 may each independently be an integer from 1 to        5,    -   R₁ to R₄, R₇ to R₁₀, R′, and R″ may each independently be        selected from hydrogen, deuterium, a deuterium-containing group,        —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro        group, an amidino group, a hydrazine group, a hydrazone group, a        carboxylic acid group or a salt thereof, a sulfonic acid group        or a salt thereof, a phosphoric acid group or a salt thereof, a        substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted        or unsubstituted C₂-C₆₀ alkenyl group, a substituted or        unsubstituted C₂-C₆₀ alkynyl group, a substituted or        unsubstituted C₁-C₆₀ alkoxy group, a substituted or        unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or        unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or        unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or        unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted        C₇-C₆₀ alkylaryl group, a substituted or unsubstituted C₆-C₆₀        aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio        group, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, a        substituted or unsubstituted C₁-C₆₀ heteroaryl group, a        substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a        substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a        substituted or unsubstituted C₂-C₆₀ heteroarylalkyl group, a        substituted or unsubstituted C₂-C₆₀ alkylheteroaryl group, a        substituted or unsubstituted monovalent non-aromatic condensed        polycyclic group, a substituted or unsubstituted monovalent        non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂),        —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉),    -   c1 to c4 and c7 may each independently be an integer from 1 to        5,    -   Z₁ to Z₄ may each independently be deuterium or a        deuterium-containing group,    -   a1 to a4 and n1 to n4 may each independently be an integer from        0 to 20,    -   i) when X₅₁ is O, S, C(═O), or N, the sum of n1 to n4 may be 1        or more, ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇),        or Ge(R₇), a) R₇ may be deuterium or a deuterium-containing        group; b) the sum of n1 to n4 may be 1 or more; or c) R₇ may be        deuterium or a deuterium-containing group and the sum of n1 to        n4 may be 1 or more, and iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈),        or Ge(R₇)(R₈), a) at least one selected from R₇ and R₈ may be        deuterium or a deuterium-containing group; b) the sum of n1 to        n4 may be 1 or more; or c) at least one selected from R₇ and R₈        may be deuterium or a deuterium-containing group and the sum of        n1 to n4 may be 1 or more,    -   two of a plurality of neighboring groups R₁ may be optionally        linked to each other to form a C₅-C₃₀ carbocyclic group        unsubstituted or substituted with at least one R_(10a) or a        C₁-C₃₀ heterocyclic group unsubstituted or substituted with at        least one R_(10a),    -   two of a plurality of neighboring groups R₂ may be optionally        linked to each other to form a C₅-C₃₀ carbocyclic group that is        unsubstituted or substituted with at least one R_(10a) or a        C₁-C₃₀ heterocyclic group that is unsubstituted or substituted        with at least one R_(10a),    -   two of a plurality of neighboring groups R₃ may be optionally        linked to each other to form a C₅-C₃₀ carbocyclic group        unsubstituted or substituted with at least one R_(10a) or a        C₁-C₃₀ heterocyclic group unsubstituted or substituted with at        least one R_(10a),    -   two of a plurality of neighboring groups R₄ may be optionally        linked to each other to form a C₅-C₃₀ carbocyclic group        unsubstituted or substituted with at least one R_(10a) or a        C₁-C₃₀ heterocyclic group unsubstituted or substituted with at        least one R_(10a), two or more neighboring groups selected from        R₁ to R₄, R₇ to R₁₀, R′, and R″ may be optionally linked to form        a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at        least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted        or substituted with at least one R_(10a),    -   R_(10a) has the same definition as R₁,    -   at least one substituent of the substituted C₅-C₃₀ carbocyclic        group, substituted C₁-C₃₀ heterocyclic group, substituted C₁-C₆₀        alkyl group, substituted C₂-C₆₀ alkenyl group, substituted        C₂-C₆₀ alkynyl group, substituted C₁-C₆₀ alkoxy group,        substituted C₃-C₁₀ cycloalkyl group, substituted C₁-C₁₀        heterocycloalkyl group, substituted C₃-C₁₀ cycloalkenyl group,        substituted C₁-C₁₀ heterocycloalkenyl group, substituted C₆-C₆₀        aryl group, substituted C₇-C₆₀ alkylaryl group, substituted        C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group,        substituted C₇-C₆₀ arylalkyl group, substituted C₁-C₆₀        heteroaryl group, substituted C₁-C₆₀ heteroaryloxy group,        substituted C₁-C₆₀ heteroarylthio group, substituted C₂-C₆₀        heteroarylalkyl group, substituted C₂-C₆₀ alkylheteroaryl group,        substituted monovalent non-aromatic condensed polycyclic group        and substituted monovalent non-aromatic condensed        heteropolycyclic group may be selected from:    -   deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,        —CFH₂, a hydroxyl group, a cyano group, a nitro group, an        amidino group, a hydrazine group, a hydrazone group, a        carboxylic acid group or a salt thereof, a sulfonic acid group        or a salt thereof, a phosphoric acid group or a salt thereof, a        C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, and a C₁-C₆₀ alkoxy group;    -   a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, and a C₁-C₆₀ alkoxy group, each substituted with at least        one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H,        —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazine group, a hydrazone        group, a carboxylic acid group or a salt thereof, a sulfonic        acid group or a salt thereof, a phosphoric acid group or a salt        thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl        group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl        group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀        aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl        group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group,        a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a        C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic        condensed polycyclic group, a monovalent non-aromatic condensed        heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅),        —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy        group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a        C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀        heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀        alkylheteroaryl group, a monovalent non-aromatic condensed        polycyclic group, and a monovalent non-aromatic condensed        heteropolycyclic group;    -   a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a        C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a        C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy        group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a        C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀        heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀        alkylheteroaryl group, a monovalent non-aromatic condensed        polycyclic group, and a monovalent non-aromatic condensed        heteropolycyclic group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,        —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro        group, an amidino group, a hydrazine group, a hydrazone group, a        carboxylic acid group or a salt thereof, a sulfonic acid group        or a salt thereof, a phosphoric acid group or a salt thereof, a        C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl        group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a        C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a        C₁-C₆₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀        alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio        group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a        C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a        C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a        monovalent non-aromatic condensed polycyclic group, a monovalent        non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂),        —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇) and —P(═O)(Q₂₈)(Q₂₉); and        —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and        —P(═O)(Q₃₈)(Q₃₉); wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and        Q₃₁ to Q₃₉ may each independently be selected from hydrogen,        deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a        nitro group, an amidino group, a hydrazine group, a hydrazone        group, a carboxylic acid group or a salt thereof, a sulfonic        acid group or a salt thereof, a phosphoric acid group or a salt        thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted        with at least one selected from deuterium, a C₁-C₆₀ alkyl group,        and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀        alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group,        a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a        C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀        aryl group substituted with at least one selected from        deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a        C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀        arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀        heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀        heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a        monovalent non-aromatic condensed polycyclic group, and a        monovalent non-aromatic condensed heteropolycyclic group.

According to an aspect of another embodiment, an organic light-emittingdevice includes:

-   -   a first electrode;    -   a second electrode; and    -   an organic layer disposed between the first electrode and the        second electrode,    -   wherein the organic layer includes an emission layer and at        least one organometallic compound represented by Formula 1.

The organometallic compound in the organic layer may function as adopant.

According to an aspect of another embodiment, a diagnostic compositionincludes at least one organometallic compound represented by Formula 1.

BRIEF DESCRIPTION OF THE DRAWING

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the FIGURE which is a schematic cross-sectional view ofan organic light-emitting device according to an embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein.

Accordingly, the embodiments are merely described below, by referring tothe FIGURES, to explain aspects of the present description. As usedherein, the term “and/or” includes any and all combinations of one ormore of the associated listed items. Expressions such as “at least oneof,” when preceding a list of elements, modify the entire list ofelements and do not modify the individual elements of the list.

It will be understood that when an element is referred to as being “on”another element, it can be directly in contact with the other element orintervening elements may be present therebetween. In contrast, when anelement is referred to as being “directly on” another element, there areno intervening elements present.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, and/or sections, these elements, components, regions, layers,and/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer, orsection from another element, component, region, layer, or section.Thus, a first element, component, region, layer, or section discussedbelow could be termed a second element, component, region, layer, orsection without departing from the teachings of the present embodiments.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

The term “or” means “and/or.” It will be further understood that theterms “comprises” and/or “comprising,” or “includes” and/or “including”when used in this specification, specify the presence of statedfeatures, regions, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

In an embodiment, an organometallic compound represented by Formula 1below is provided:

M in Formula 1 may be beryllium (Be), magnesium (Mg), aluminum (Al),calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu),zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru),rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt),or gold (Au).

In an embodiment, M may be Pt, Pd, or Au, but embodiments of the presentdisclosure are not limited thereto.

X₁ in Formula 1 may be a chemical bond (for example, a single bond or acovalent bond), O, S, N(R′), P(R′), B(R′), C(R′)(R″), or Si(R′)(R″). R′and R″ are the same as described above. When X₁ is a chemical bond, Y₁and M may directly be linked to each other.

For example, X₁ may be O or S, but embodiments of the present disclosureare not limited thereto.

X₂ to X₄ in Formula 1 may each independently be N or C, two selectedfrom X₂ to X₄ may each be N, and the remainder may be C.

A bond between X₁ or Y₁ and M in Formula 1 may be a covalent bond, onebond selected from a bond between X₂ and M, a bond between X₃ and M, anda bond between X₄ and M may be a covalent bond, and the remaining twobonds may be coordinate bonds. Thus, the organometallic compoundrepresented by Formula 1 may be electrically neutral.

In one or more embodiments, in Formula 1,

-   -   i) X₂ and X₄ may each be N, X₃ may be C, a bond between X₂ and M        and a bond between X₄ and M may each be a coordinate bond, and a        bond between X₃, and M may be a covalent bond, or    -   i) X₂ and X₃ may each be N, X₄ may be C, a bond between X₂ and M        and a bond between X₃ and M may each be a coordinate bond, and a        bond between X₄ and M may be a covalent bond, or    -   iii) X₃ and X₄ may be N, X₂ may be C, a bond between X₃ and M        and a bond between X₄ and M may each be a coordinate bond, and a        bond between X₂ and M may be a covalent bond, but embodiments of        the present disclosure are not limited thereto.

In Formula 1, Y₁ and Y₃ to Y₅ may each independently be C or N, andamong pairs of X₂ and Y₃, X₂ and Y₄, Y₄ and Y₅, X₅₁ and Y₃, and X₅₁ andY₅, the components in each pair may be linked via a chemical bond.Accordingly, ring CY₅ in the Formula 1 may be a 5-membered ringcondensed with ring CY₂.

Ring CY₁ to ring CY₅ in Formula 1 may each independently be selectedfrom a C₅-C₃₀ carbocyclic group, and a C₁-C₃₀ heterocyclic group, andeach of ring CY₁, ring CY₃, and ring CY₄ may not be a benzimidazolegroup.

For example, ring CY₁ to ring CY₄ may each independently selected from:i) a first ring, ii) a second ring, iii) a condensed ring in which twoor more first rings are condensed with each other, iv) a condensed ringin which two or more second rings are condensed with each other, and v)a condensed ring in which one or more first rings and one or more secondrings are condensed with each other, wherein

-   -   the first ring may be selected from a cyclopentane group, a        cyclopentadiene group, a furan group, a thiophene group, a        pyrrole group, a silole group, an indene group, a benzofuran        group, a benzothiophene group, an indole group, a benzosilole        group, an oxazole group, an isoxazole group, an oxadiazole        group, an isozadiazole group, an oxatriazole group, an        isoxatriazole group, a thiazole group, an isothiazole group, a        thiadiazole group, an isothiadiazole group, a thiatriazole        group, an isothiatriazole group, a pyrazole group, an imidazole        group, a triazole group, a tetrazole group, an azasilole group,        a diazasilole group, and a triazasilole group,    -   the second ring may be selected from an adamantane group, a        norbornane group, a norbornene group, a cyclohexane group, a        cyclohexene group, a benzene group, a pyridine group, a        pyrimidine group, a pyrazine group, a pyridazine group, and a        triazine group, and    -   each of ring CY₁ to ring CY₄ may not be a benzimidazole group.

In an embodiment, ring CY₁ to ring CY₄ may each independently beselected from a benzene group, a naphthalene group, an anthracene group,a phenanthrene group, a triphenylene group, a pyrene group, a chrysenegroup, cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, afuran group, a thiophene group, a silole group, an indene group, afluorene group, an indole group, a carbazole group, a benzofuran group,a dibenzofuran group, a benzothiophene group, a dibenzothiophene group,a benzosilole group, a dibenzosilole group, an azafluorene group, anazacarbazole group, an azadibenzofuran group, an azadibenzothiophenegroup, an azadibenzosilole group, a pyridine group, a pyrimidine group,a pyrazine group, a pyridazine group, a triazine group, a quinolinegroup, an isoquinoline group, a quinoxaline group, a quinazoline group,a phenanthroline group, a pyrrole group, a pyrazole group, an imidazolegroup, a triazole group, an oxazole group, an isooxazole group, athiazole group, an isothiazole group, an oxadiazole group, a thiadiazolegroup, a 5,6,7,8-tetrahydroisoquinoline group, and a5,6,7,8-tetrahydroquinoline group, but embodiments of the presentdisclosure are not limited thereto.

A cyclometalated ring formed by ring CY₅, ring CY₂, ring CY₃, and M inFormula 1 may be a 6-membered ring.

In an embodiment, X₂ of ring CY₅, X₃ of ring CY₃, and X₄ of ring CY₄ inFormula 1 may not constitute a carbine moiety. That is, regardingFormula 1, 1) when X₂ is C, a bond between X₂ and M may be a covalentbond, 2) when X₃ is C, a bond between X₃ and M may be a covalent bond,and 3) when X₄ is C, a bond between X₄ and M may be a covalent bond.

Regarding Formula 1, X₅₁ may be O, S, N-[(L₇)_(b7)-(R₇)_(c7)],C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═O), N, C(R₇), Si(R₇), and Ge(R₇),and R₇ and R₈ may optionally be linked via a single bond, a double bond,or a first linking group to form a C₅-C₃₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀heterocyclic group unsubstituted or substituted with at least oneR_(10a). Herein, the C₅-C₃₀ carbocyclic group and the C₁-C₃₀heterocyclic group may be understood by referring to the descriptionsabout i) the first ring, ii) the second ring, iii) the condensed ring inwhich two or more first rings are condensed with each other, iv) thecondensed ring in which two or more second rings are condensed with eachother, and v) the condensed ring in which one or more first rings andone or more second rings are condensed with each other, and R_(10a) maybe understood by referring to the description about R₁, and L₇, b7, R₇,R₈, and c7 will be described in detail later.

The first linking group may be selected from *—O—*′, *—S—*′,*—C(R₅)(R₆)—*′, *—C(R₅)═*′, *═C(R₆)—*′, *—C(R₅)═C(R₆)—*′, *—C(═O)—*′,*—C(═S)—*′, *—C≡C—*′, *—N(R₅)—*′, *—Si(R₅)(R₆)—*′, and *—P(R₅)(R₆)—*′,and R₅ and R₆ are the same as described in connection with R₁, and eachof * and *′ indicates a binding site to a neighboring atom.

In one or more embodiments, in Formula 1,

-   -   i) Y₃ to Y₅ may each be C, a bond between X₅₁ and Y₃ and a bond        between X₅₁ and Y₅ may each be a single bond, and X₅₁ may be O,        S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈),        or C(═O),    -   ii) Y₃ and Y₄ may each be C, Y₅ may be N, a bond between X₅₁ and        Y₃ may be a double bond, a bond between X₅₁ and Y₅ may be a        single bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇),    -   iii) Y₃ and Y₅ may each be C, Y₄ may be N, a bond between X₅₁        and Y₃ may be a single bond, a bond between X₅₁ and Y₅ may be a        double bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇),    -   iv) Y₃ may be N, Y₄ and Y₅ may each be C, a bond between X₅₁ and        Y₃ may be a single bond, a bond between X₅₁ and Y₅ may be a        double bond, and X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇), or    -   v) Y₃ to Y₅ may each be C, a bond between X₅₁ and Y₃ may be a        double bond, a bond between X₅₁ and Y₅ may be a single bond, and        X₅₁ may be N, C(R₇), Si(R₇), or Ge(R₇), but embodiments are not        limited thereto.

T₁ and T₂ in Formula 1 may each independently be a single bond, a doublebond, *—N(R₉)—*′, *—B(R₉)—*′, *—P(R₉)—*′, *—C(R₉)(R₁₀)—*′,*—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′,*—S(═O)—*′, *—S(═O)₂—*′, *—C(R₉)═*′, *═C(R₉)—*′, *—C(R₉)═C(R₁₀)—*′,*—C(═S)—*′, or *—C≡C—*′, R₉ and R₁₀ may optionally be linked via asingle bond, a double bond, or a second linking group to form a C₅-C₃₀carbocyclic group unsubstituted or substituted with at least one R_(10a)or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with atleast one R_(10a). Herein, the C₅-C₃₀ carbocyclic group and the C₁-C₃₀heterocyclic group may be understood by referring to the descriptionsabout i) the first ring, ii) the second ring, iii) the condensed ring inwhich two or more first rings are condensed with each other, iv) thecondensed ring in which two or more second rings are condensed with eachother, and v) the condensed ring in which one or more first rings andone or more second rings are condensed with each other, and R_(10a) maybe understood by referring to the description about R₁, and the secondlinking group may be understood by referring to the description aboutthe first linking group.

In an embodiment, T₁ and T₂ in Formula 1 may be a single bond, butembodiments are not limited thereto.

L₁ to L₄ and L₇ in Formula 1 may each independently be selected from asingle bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group,and a substituted or unsubstituted C₁-C₃₀ heterocyclic group.

For example, L₁ to L₄ and L₇ in Formula 1 may each independently beselected from:

-   -   a single bond, a benzene group, a naphthalene group, an        anthracene group, a phenanthrene group, a triphenylene group, a        pyrene group, a chrysene group, cyclopentadiene group, a furan        group, a thiophene group, a silole group, an indene group, a        fluorene group, an indole group, a carbazole group, a benzofuran        group, a dibenzofuran group, a benzothiophene group, a        dibenzothiophene group, a benzosilole group, a dibenzosilole        group, an azafluorene group, an azacarbazole group, an        azadibenzofuran group, an azadibenzothiophene group, an        azadibenzosilole group, a pyridine group, a pyrimidine group, a        pyrazine group, a pyridazine group, a triazine group, a        quinoline group, an isoquinoline group, a quinoxaline group, a        quinazoline group, a phenanthroline group, a pyrrole group, a        pyrazole group, an imidazole group, a triazole group, an oxazole        group, an isooxazole group, a thiazole group, an isothiazole        group, an oxadiazole group, a thiadiazole group, a benzopyrazole        group, a benzimidazole group, a benzoxazole group, a        benzothiazole group, a benzooxadiazole group and a        benzothiadiazole group; and    -   a benzene group, a naphthalene group, an anthracene group, a        phenanthrene group, a triphenylene group, a pyrene group, a        chrysene group, cyclopentadiene group, a furan group, a        thiophene group, a silole group, an indene group, a fluorene        group, an indole group, a carbazole group, a benzofuran group, a        dibenzofuran group, a benzothiophene group, a dibenzothiophene        group, a benzosilole group, a dibenzosilole group, an        azafluorene group, an azacarbazole group, an azadibenzofuran        group, an azadibenzothiophene group, an azadibenzosilole group,        a pyridine group, a pyrimidine group, a pyrazine group, a        pyridazine group, a triazine group, a quinoline group, an        isoquinoline group, a quinoxaline group, a quinazoline group, a        phenanthroline group, a pyrrole group, a pyrazole group, an        imidazole group, a triazole group, an oxazole group, an        isooxazole group, a thiazole group, an isothiazole group, an        oxadiazole group, a thiadiazole group, a benzopyrazole group, a        benzimidazole group, a benzoxazole group, a benzothiazole group,        a benzooxadiazole group and a benzothiadiazole group, each        substituted with at least one selected from deuterium, —F, —Cl,        —Br, —I, a hydroxyl group, a cyano group, a nitro group, an        amino group, an amidino group, a hydrazine group, a hydrazone        group, a carboxylic acid group or a salt thereof, a sulfonic        acid group or a salt thereof, a phosphoric acid group or a salt        thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkyl group substituted        with at least one deuterium, a C₁-C₂₀ alkoxy group, a phenyl        group, a phenyl group substituted with at least one deuterium, a        biphenyl group, a naphthyl group, a pyridinyl group, a        pyrimidinyl group, a triazinyl group, a fluorenyl group, a        dimethylfluorenyl group, a diphenylfluorenyl group, a carbazolyl        group, a phenylcarbazolyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolyl group, a        dimethyldibenzosilolyl group, a diphenyldibenzosilolyl group,        —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and        —P(═O)(Q₃₈)(Q₃₉);    -   Q₃₁ to Q₃₉ may each independently be selected from:    -   —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂,        —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CH₃, —CD₂CD₃,        —CD₂CD₂H, and —CD₂CDH₂;    -   an n-propyl group, an iso-propyl group, an n-butyl group, an        iso-butyl group, a sec-butyl group, a tert-butyl group, an        n-pentyl group, an isopentyl group, a sec-pentyl group, a        tert-pentyl group, a phenyl group, and a naphthyl group; and    -   an n-propyl group, an iso-propyl group, an n-butyl group, an        iso-butyl group, a sec-butyl group, a tert-butyl group, an        n-pentyl group, an isopentyl group, a sec-pentyl group, a        tert-pentyl group, a phenyl group, and a naphthyl group, each        substituted with at least one selected from deuterium, a C₁ to        C₁₀ alkyl group, and a phenyl group;    -   but embodiments of the present disclosure are not limited        thereto.

b1 to b4 and b7 in Formula 1 indicate numbers of L₁ to L₄ and L₇,respectively, and may each independently be an integer from 1 to 5. Whenb1 is two or more, two or more groups L₁ may be identical to ordifferent from each other. b2 to b4 and b7 may each be the same asdescribed in connection with b1.

In an embodiment, L₁ to L₄ and L₇ in Formula 1 may each independently beselected from:

-   -   a single bond; and    -   a benzene group unsubstituted or substituted with at least one        selected from deuterium, —F, a cyano group, a C₁-C₂₀ alkyl        group, a C₁-C₂₀ alkyl group substituted with at least one        deuterium, a phenyl group, a phenyl group substituted with at        least one deuterium, a biphenyl group, a naphthyl group, a        pyridinyl group, a pyrimidinyl group, a triazinyl group, a        fluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl        group, a carbazolyl group, a phenylcarbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a dimethyldibenzosilolyl group and a        diphenyldibenzosilolyl group; and

b1 to b4 and b7 in Formula 1 may be 1 or 2, but embodiments of thepresent disclosure are not limited thereto.

In an embodiment, b1 to b4 and b7 in Formula 1 may be 1 or 2, butembodiments of the present disclosure are not limited thereto.

R₁ to R₄, R₇ to R₁₀, R′, and R″ may each independently be selected fromhydrogen, deuterium, deuterium-containing group, —F, —Cl, —Br, —I, —SF₅,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkylgroup, a substituted or unsubstituted C₂-C₆₀ alkenyl group, asubstituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted orunsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₇-C₆₀ alkylaryl group, a substituted or unsubstitutedC₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthiogroup, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstitutedC₁-C₆₀ heteroarylthio group, a substituted or unsubstituted C₂-C₆₀heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀alkylheteroaryl group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂),—Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉). Thedeuterium-containing group and Q₁ to Q₉ are the same as described above.

For example, R₁ to R₄, R₇ to R₁₀, R′, and R″ may each independently beselected from:

-   -   hydrogen, deuterium, a deuterium-containing group, —F, —Cl, —Br,        —I, a hydroxyl group, a cyano group, a nitro group, an amino        group, an amidino group, a hydrazine group, a hydrazone group, a        carboxylic acid group or a salt thereof, a sulfonic acid group        or a salt thereof, a phosphoric acid group or a salt thereof,        —SF₅, a C₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;    -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted        with at least one selected from deuterium, —F, —Cl, —Br, —I,        —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a        cyano group, a nitro group, an amino group, an amidino group, a        hydrazine group, a hydrazone group, a carboxylic acid group or a        salt thereof, a sulfonic acid group or a salt thereof, a        phosphoric acid group or a salt thereof, a C₁-C₁₀ alkyl group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a pyridinyl group, and a pyrimidinyl group;    -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a fluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a pyrrolyl group, a        thiophenyl group, a furanyl group, an imidazolyl group, a        pyrazolyl group, a thiazolyl group, an isothiazolyl group, an        oxazolyl group, an isoxazolyl group, a pyridinyl group, a        pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an        isoindolyl group, an indolyl group, an indazolyl group, a        purinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, an imidazopyridinyl group, and an        imidazopyrimidinyl group;    -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a fluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a pyrrolyl group, a        thiophenyl group, a furanyl group, an imidazolyl group, a        pyrazolyl group, a thiazolyl group, an isothiazolyl group, an        oxazolyl group, an isoxazolyl group, a pyridinyl group, a        pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an        isoindolyl group, an indolyl group, an indazolyl group, a        purinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, an imidazopyridinyl group, and an        imidazopyrimidinyl group, each substituted with at least one        selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂,        —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro        group, an amino group, an amidino group, a hydrazine group, a        hydrazone group, a carboxylic acid group or a salt thereof, a        sulfonic acid group or a salt thereof, a phosphoric acid group        or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group,        a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a fluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a pyrrolyl group, a        thiophenyl group, a furanyl group, an imidazolyl group, a        pyrazolyl group, a thiazolyl group, an isothiazolyl group, an        oxazolyl group, an isoxazolyl group, a pyridinyl group, a        pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an        isoindolyl group, an indolyl group, an indazolyl group, a        purinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, an imidazopyridinyl group, an        imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and    -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉);

Herein, Q₁ to Q₉ and Q₃₃ to Q₃₅ may be understood by referring to thedescription presented above.

In some embodiments, R₁ to R₄, R₇ to R₁₀, R′, and R″ may eachindependently be selected from:

-   -   hydrogen, deuterium, deuterium-containing group, —F, a cyano        group, a nitro group, —SF₅, a methyl group, an ethyl group, an        n-propyl group, an iso-propyl group, an n-butyl group, an        iso-butyl group, a sec-butyl group, a tert-butyl group, an        n-pentyl group, an isopentyl group, a sec-pentyl group, a        tert-pentyl group, an n-hexyl group, an isohexyl group, a        sec-hexyl group, a tert-hexyl group, an n-heptyl group, an        isoheptyl group, a sec-heptyl group, a tert-heptyl group, an        n-octyl group, an isooctyl group, a sec-octyl group, a        tert-octyl group, an n-nonyl group, an isononyl group, a        sec-nonyl group, a tert-nonyl group, an n-decyl group, an        isodecyl group, a sec-decyl group, a tert-decyl group, a methoxy        group, an ethoxy group, a propoxy group, a butoxy group, a        pentoxy group, a cyclopentyl group, a cyclohexyl group, a        cycloheptyl group, a cycloctyl group, an adamantanyl group, a        norbornanyl group, a norbornenyl group, a cyclopentenyl group, a        cyclohexenyl group, a cycloheptenyl group, a        bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a        bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a        phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, a pyridinyl group, a        pyrimidinyl group, a fluorenyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, and a        dibenzosilolyl group;    -   a methyl group, an ethyl group, an n-propyl group, an iso-propyl        group, an n-butyl group, an iso-butyl group, a sec-butyl group,        a tert-butyl group, an n-pentyl group, an isopentyl group, a        sec-pentyl group, a tert-pentyl group, an n-hexyl group, an        isohexyl group, a sec-hexyl group, a tert-hexyl group, an        n-heptyl group, an isoheptyl group, a sec-heptyl group, a        tert-heptyl group, an n-octyl group, an isooctyl group, a        sec-octyl group, a tert-octyl group, an n-nonyl group, an        isononyl group, a sec-nonyl group, a tert-nonyl group, an        n-decyl group, an isodecyl group, a sec-decyl group, a        tert-decyl group, a methoxy group, an ethoxy group, a propoxy        group, a butoxy group, a pentoxy group, a cyclopentyl group, a        cyclohexyl group, a cycloheptyl group, a cycloctyl group, an        adamantanyl group, a norbornanyl group, a norbornenyl group, a        cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl        group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl        group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl        group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl        group, a terphenyl group, a naphthyl group, a pyridinyl group, a        pyrimidinyl group, a fluorenyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, and a        dibenzosilolyl group, each substituted with at least one        selected from deuterium, —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,        —CFH₂, a cyano group, a nitro group, a C₁-C₁₀ alkyl group, a        C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a        cycloheptyl group, a cycloctyl group, an adamantanyl group, a        norbornanyl group, a norbornenyl group, a cyclopentenyl group, a        cyclohexenyl group, a cycloheptenyl group, a        bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a        bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a        phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a        terphenyl group, a naphthyl group, a pyridinyl group, a        pyrimidinyl group, a fluorenyl group, a carbazolyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); and    -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉);    -   wherein Q₁ to Q₉ and Q₃₃ to Q₃₅ are the same as described above,        but embodiments are not limited thereto.

c1 to c4 and c7 in Formula 1 indicate numbers of R₁ to R₄ and R₇,respectively, and may each independently be an integer from 1 to 5 (forexample, 1, 2, and 3). When c1 is two or more, two or more groups R₁ maybe identical to or different from each other. c2 to c4 and c7 may beunderstood by referring to the description about c1.

Z₁ to Z₄ in Formula 1 may each independently be deuterium or adeuterium-containing group.

For example, the deuterium-containing group is a first group substitutedwith at least one deuterium, and the first group may be selected from asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₇-C₆₀alkylaryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstitutedC₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀heteroarylthio group, a substituted or unsubstituted C₂-C₆₀heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀alkylheteroaryl group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

The term “a deuterium-containing group” as used herein refers to anygroup including at least one deuterium, which may be further substitutedwith substituents other than deuterium. For example, the term “adeuterium-containing group” as used herein may include a phenyl groupsubstituted with one deuterium, a phenyl group substituted with fivedeuterium and not containing hydrogen (see Formula 11-1), a phenyl groupsubstituted with four deuterium and one tert-butyl group (see Formulae11-10 to 11-12), a phenyl group substituted with four deuterium and one—C(CD₃)₃ and not containing hydrogen (see Formulae 11-7 to 11-9), —CDH₂,—CD₃, or the like. Herein, for example, the “phenyl group substitutedwith one deuterium” refers to a deuterium-containing group in which thefirst group is a “phenyl group,” and the “phenyl group substituted withfour deuterium and one tert-butyl group” refers to adeuterium-containing group in which the first group is “a phenyl groupsubstituted with a tert-butyl group.”

In an embodiment, the deuterium-containing group may be a first groupsubstituted with at least one deuterium,

-   -   the first group may be selected from:    -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group;    -   a C₁-C₂₀ alkyl group and a C₁-C₂₀ alkoxy group, each substituted        with at least one selected from —F, —Cl, —Br, —I, —CD₃, —CD₂H,        —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a        nitro group, an amino group, an amidino group, a hydrazine        group, a hydrazone group, a carboxylic acid group or a salt        thereof, a sulfonic acid group or a salt thereof, a phosphoric        acid group or a salt thereof, a C₁-C₁₀ alkyl group, a        cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a pyridinyl group, and a pyrimidinyl group;    -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a fluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a pyrrolyl group, a        thiophenyl group, a furanyl group, an imidazolyl group, a        pyrazolyl group, a thiazolyl group, an isothiazolyl group, an        oxazolyl group, an isoxazolyl group, a pyridinyl group, a        pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an        isoindolyl group, an indolyl group, an indazolyl group, a        purinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, an imidazopyridinyl group, and an        imidazopyrimidinyl group;    -   a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a        cycloctyl group, an adamantanyl group, a norbornanyl group, a        norbornenyl group, a cyclopentenyl group, a cyclohexenyl group,        a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a        bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a        bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀        alkyl)phenyl group, a biphenyl group, a terphenyl group, a        naphthyl group, a fluorenyl group, a phenanthrenyl group, an        anthracenyl group, a fluoranthenyl group, a triphenylenyl group,        a pyrenyl group, a chrysenyl group, a pyrrolyl group, a        thiophenyl group, a furanyl group, an imidazolyl group, a        pyrazolyl group, a thiazolyl group, an isothiazolyl group, an        oxazolyl group, an isoxazolyl group, a pyridinyl group, a        pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an        isoindolyl group, an indolyl group, an indazolyl group, a        purinyl group, a quinolinyl group, an isoquinolinyl group, a        benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl        group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl        group, a benzimidazolyl group, a benzofuranyl group, a        benzothiophenyl group, an isobenzothiazolyl group, a        benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group,        a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a        dibenzofuranyl group, a dibenzothiophenyl group, a        dibenzosilolyl group, a benzocarbazolyl group, a        dibenzocarbazolyl group, an imidazopyridinyl group, and an        imidazopyrimidinyl group, each substituted with at least one        selected from —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,        —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino        group, an amidino group, a hydrazine group, a hydrazone group, a        carboxylic acid group or a salt thereof, a sulfonic acid group        or a salt thereof, a phosphoric acid group or a salt thereof, a        C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group,        a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an        adamantanyl group, a norbornanyl group, a norbornenyl group, a        cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl        group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl        group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl        group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl        group, a terphenyl group, a naphthyl group, a fluorenyl group, a        phenanthrenyl group, an anthracenyl group, a fluoranthenyl        group, a triphenylenyl group, a pyrenyl group, a chrysenyl        group, a pyrrolyl group, a thiophenyl group, a furanyl group, an        imidazolyl group, a pyrazolyl group, a thiazolyl group, an        isothiazolyl group, an oxazolyl group, an isoxazolyl group, a        pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a        pyridazinyl group, an isoindolyl group, an indolyl group, an        indazolyl group, a purinyl group, a quinolinyl group, an        isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl        group, a quinazolinyl group, a cinnolinyl group, a carbazolyl        group, a phenanthrolinyl group, a benzimidazolyl group, a        benzofuranyl group, a benzothiophenyl group, an        isobenzothiazolyl group, a benzoxazolyl group, an        isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an        oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a        dibenzothiophenyl group, a dibenzosilolyl group, a        benzocarbazolyl group, a dibenzocarbazolyl group, an        imidazopyridinyl group, an imidazopyrimidinyl group, and        —Si(Q₃₃)(Q₃₄)(Q₃₅); and    -   —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉);

Herein, Q₁ to Q₉ and Q₃₃ to Q₃₅ may be understood by referring to thedescription presented above.

In an embodiment, the deuterium-containing group may be a first groupsubstituted with at least one deuterium, and the first group may beselected from a C₁-C₂₀ alkyl group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cycloctyl group, an adamantanyl group, anorbornanyl group, a norbornenyl group, a cyclopentenyl group, acyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group,a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, abicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group,a biphenyl group and a terphenyl group, each unsubstituted orsubstituted with at least one selected from —F, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a cyano group, a C₁-C₁₀ alkyl group, a cyclopentyl group,a cyclohexyl group, a cycloheptyl group, a cycloctyl group, anadamantanyl group, a norbornanyl group, a norbornenyl group, acyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, abicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, abicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group,a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group and a terphenyl group.

In an embodiment, the deuterium-containing group i) may not includehydrogen or ii) may include at least one C₁-C₁₀ alkyl group.

For example, in the deuterium-containing group, “all hydrogen” of the“first group” is replaced with “deuterium” and thus, hydrogen is notpresent (for example, such the deuterium-containing group may beselected from —CD₃, —CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃,—CD₂-CD(CD₃)₂, —CD₂-CD₂(CD₃), —CD(CD₃)-C(CD₃)₃, —CD(CD₃)-CD(CD₃)₂,—CD(CD₃)-CD₂(CD₃), —C(CD₃)₂-C(CD₃)₃, —C(CD₃)₂-CD(CD₃)₂,—C(CD₃)₂-CD₂(CD₃), and Formulae 11-1 to 11-9).

In some embodiments, the deuterium-containing group may include at leastone C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, ann-propyl group, an iso-propyl group, an n-butyl group, an iso-butylgroup, a tert-butyl group, a sec-butyl group, an n-pentyl group, anisopentyl group, a tert-pentyl group, a sec-pentyl group, etc.), andsuch a deuterium-containing group may be, for example, one of Formulae11-10 to 11-12, but embodiments are not limited thereto.

In some embodiments, R₁ to R₄, R₇ to R₁₀, R′ and R″ may eachindependently selected from hydrogen, deuterium, —F, a cyano group, anitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂,—CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃, —CD₂-CD(CD₃)₂,—CD₂-CD₂(CD₃), —CD(CD₃)-C(CD₃)₃, —CD(CD₃)-CD(CD₃)₂, —CD(CD₃)-CD₂(CD₃),—C(CD₃)₂-C(CD₃)₃, —C(CD₃)₂-CD(CD₃)₂, —C(CD₃)₂-CD₂(CD₃), a grouprepresented by Formula 9-1 to 9-19, a group represented by Formulae 10-1to 10-232, a group represented by Formulae 11-1 to 11-41, and—Si(Q₁)(Q₂)(Q₃) (Q₁ to Q₃ are the same as described above),

-   -   Z₁ to Z₄ may each independently be deuterium, —CD₃, —CD₂H,        —CDH₂, —CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃,        —CD₂-CD(CD₃)₂, —CD₂-CD₂(CD₃), —CD(CD₃)-C(CD₃)₃,        —CD(CD₃)-CD(CD₃)₂, —CD(CD₃)-CD₂(CD₃), —C(CD₃)₂-C(CD₃)₃,        —C(CD₃)₂-CD(CD₃)₂, —C(CD₃)₂-CD₂(CD₃), and a group represented by        one of Formulae 9-14 to 9-19, 10-11, 10-12, and 11-1 to 11-41,        but embodiments are not limited thereto:

Regarding Formulae 9-1 to 9-19, 10-1 to 10-232 and 11-1 to 11-41, *indicates a binding site to neighboring atoms, Ph is a phenyl group, andTMS is a trimethylsilyl group.

In one or more embodiments, the deuterium-containing group may beselected from —CD₃, —CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃,—CD₂-CD(CD₃)₂, —CD₂-CD₂(CD₃), —CD(CD₃)-C(CD₃)₃, —CD(CD₃)-CD(CD₃)₂,—CD(CD₃)-CD₂(CD₃), —C(CD₃)₂-C(CD₃)₃, —C(CD₃)₂-CD(CD₃)₂,—C(CD₃)₂-CD₂(CD₃), and a group represented by one of Formula 11-1 to11-41, but embodiments are not limited thereto.

Regarding Formula 1, a1 to a4 respectively indicate numbers of*—[(L₁)_(b1)-(R₁)_(c1)], * [(L₂)_(b2)-(R₂)_(c2)],*—[(L₃)_(b3)-(R₃)_(c3)], and *—[(L₄)_(b4)-(R₄)_(c4)], and n1 to n4respectively indicate numbers of Z₁ to Z₄, and a1 to a4 and n1 to n4 mayeach independently be an integer from 0 to 20. When a1 is two or more,two or more groups *—[(L₁)_(b1)-(R₁)_(c1)] may be identical to ordifferent from each other, when a2 is two or more, two or more groups*—[(L₂)_(b2)-(R₂)_(c2)] may be identical to or different from eachother, when a3 is two or more, two or more groups*—[(L₃)_(b3)-(R₃)_(c3)] may be identical to or different from eachother, when a4 is two or more, two or more groups*—[(L₄)_(b4)-(R₄)_(c4)] may be identical to or different from eachother, when n1 is two or more, two or more groups Z₁ may be identical toor different from each other, when n2 is two or more, two or more groupsZ₂ may be identical to or different from each other, when n3 is two ormore, two or more groups Z₃ may be identical to or different from eachother, and when n4 is two or more, two or more groups Z₄ may beidentical to or different from each other.

In Formula 1,

-   -   i) when X₅₁ is O, S, C(═O), or N, the sum of n1 to n4 may be 1        or more,    -   ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or        Ge(R₇), a) R₇ is deuterium or a deuterium-containing group; b)        the sum of n1 to n4 may be 1 or more; or c) R₇ is deuterium or a        deuterium-containing group and the sum of n1 to n4 may be 1 or        more,    -   iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), a) at        least one selected from R₇ and R₈ may be a deuterium or a        deuterium-containing group; b) the sum of n1 to n4 may be 1 or        more; or c) at least one selected from R₇ and R₈ may be        deuterium or a deuterium-containing group and the sum of n1 to        n4 may be 1 or more.

That is, Formula 1 may essentially include at least one deuterium and/orat least one deuterium-containing group.

In one or more embodiments, in Formula 1,

-   -   Y₃ to Y₅ may each be C,    -   a bond between X₅₁ and Y₃ and a bond between X₅₁ and Y₅ may each        be a single bond, and    -   a) X₅₁ may be O or S, and the sum of n1 to n4 may be 1, 2, 3, or        4; b) X₅₁ may be N[(L₇)_(b7)-(R₇)_(c7)] and R₇ may be deuterium        or a deuterium-containing group; c) X₅₁ may be        N[(L₇)_(b7)-(R₇)_(c7)], and the sum of n1 to n4 may be 1, 2, 3,        or 4; d) X₅₁ may be N[(L₇)_(b7)-(R₇)_(c7)], R₇ may be deuterium        or deuterium-containing group, and the sum of n1 to n4 may be 1,        2, 3, or 4; e) X₅₁ may be C(R₇)(R₈), and at least one selected        from R₇ and R₈ may be deuterium or a deuterium-containing group;        or f) X₅₁ may be C(R₇)(R₈), and the sum of n1 to n4 may be 1, 2,        3, or 4, but embodiments are not limited thereto.

In one or more embodiments, Formula 1 may satisfy at least one ofCondition A to Condition D:

-   -   Condition A    -   n1 may be 1, 2, 3 or 4.    -   Condition B    -   X₅₁ may be N[(L₇)_(b7)-(R₇)_(c7)] and R₇ may be deuterium or a        deuterium-containing group.    -   Condition C    -   n3 may be 1, 2 or 3.    -   Condition D    -   n4 may be 1, 2, 3 or 4.

In one or more embodiments, in Formula 1,

-   -   i) n1=n2=n3=0, and n4 may be 1, 2, 3, or 4,    -   ii) n1=n2=n4=0, and n3 may be 1, 2, 3, or 4,    -   iii) n1=n3=n4=0, and n2 may be 1, 2, 3, or 4,    -   iv) n2=n3=n4=0, and n1 may be 1, 2, 3, or 4, or    -   v) n1=n2=n3=n4=0, X₅₁ may be N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇),        Si(R₇), or Ge(R₇), and R₇ may be deuterium or a        deuterium-containing group; or    -   vi) n1=n2=0, and n3 and n4 may each independently be 1, 2, 3, or        4,    -   vii) n1=n2=n3=0, n4 may be 1, 2, 3, or 4, X₅₁ may be        N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or Ge(R₇), and R₇ may be        deuterium or a deuterium-containing group,    -   viii) n1=n2=n4=0, n3 may be 1, 2, 3, or 4, X₅₁ may be        N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or Ge(R₇), and R₇ may be        deuterium or a deuterium-containing group, or    -   ix) n2=n4=0, and n1 and n3 may each independently be 1, 2, 3, or        4, but embodiments are not limited thereto.

In one or more embodiments, regarding Formula 1,

-   -   i) X₁ may be a chemical bond, and T₁ may be a single bond, a        moiety represented by

may be a group represented by Formula CY1-B,

-   -   ii) X₁ may be O, S, N(R′), P(R′), B(R′), C(R′)(R″), Si(R′)(R″),        or N(R′)(R″), and T₁ may be a single bond, a moiety represented        by

may be a group represented by Formula CY1-A, or

-   -   iii) X₁ may be a chemical bond, and T₁ may be *—N(R₉)—*′,        *—B(R₉)—*′, *—P(R₉)—*′, *—C(R₉)(R₁₀)—*′, *—Si(R₉)(R₁₀)—*′,        *—Ge(R₉)(R₁₀)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′,        *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₉)═*′, *═C(R₉)—*′,        *—C(R₉)═C(R₁₀)—*′, *—C(═S)—*′, or *—C≡C—*′, and a moiety        represented by

may be a group represented by Formula CY1-A:

Regarding Formulae CY1-A and CY1-B, Y₁, CY₁, L₁, b1, R₁, c1, a1, Z₁, andn1 are the same as described above, Y₂ and Y₆ may each independently beN or C, and a bond between Y₁ and Y₂, a bond between Y₁ and Y₆, and abond between Y₆ and Y₂ may each be a chemical bond.

In one or more embodiments, regarding Formula 1, a moiety represented by

may be a group represented by one of Formulae CY1-1 to CY1-40:

In Formula CY1-1 to CY1-40,

-   -   Y₁, R₁, Z₁, and n1 are the same as described above, and n1 may        be an integer from 0 to 7,    -   X₁₉ may be C(R_(19a))(R_(19b)), N[(L₁₉)_(b19)-(R₁₉)_(c19)], O,        S, or Si(R_(19a))(R_(19b)),    -   L₁₉ may be the same as explained in connection with L₁;    -   b19 and c19 are the same as described in connection with b1 and        c1,    -   R₁₁ to R₁₉, R_(19a), and R_(19b) are the same as described in        connection with R₁,    -   a12 may be an integer from 0 to 2,    -   a13 may be an integer from 0 to 3,    -   a14 may be an integer from 0 to 4,    -   a15 may be an integer from 0 to 5,    -   a16 may be an integer from 0 to 6,    -   a17 may be an integer from 0 to 7,    -   *′ indicates a binding site to X₁ or M in Formula 1, and    -   * indicates a binding site to T₁ in Formula 1.

n1 in Formula CY1-1 to CY1-40 has been described based on when n1 hasits maximum value, and n1 may be an integer from 0 to 7, varyingdepending on a corresponding chemical formula. For example, n1 inFormula CY1-1 may be 0, 1, 2, 3, or 4, n1 in Formula CY1-2 may be 0, 1,2, or 3, and n1 in Formula CY1-27 may be 0, 1, 2, 3, 4, 5, 6, or 7.

In one or more embodiments, regarding Formula 1, a moiety represented by

may be a group represented by one of Formulae CY2-1 to CY2-20:

In Formulae CY2-1 to CY2-20,

-   -   X₂, R₂, Z₂, and n2 are the same as described above, and n2 may        be an integer from 0 to 3,    -   X₅₁ in Formulae CY2-1 to CY2-4 may be O, S,        N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or        C(═O),    -   X₅₁ in Formulae CY2-5 to CY2-20 may be N, C(R₇), Si(R₇), or        Ge(R₇),    -   L₇, b7, R₇, and c7 may be the same as described above,    -   a22 is an integer from 0 to 2,    -   a23 is an integer from 0 to 3,    -   * indicates a binding site to T₁ in Formula 1,    -   *′ indicates a binding site to M in Formula 1, and    -   *″ indicates a binding site to ring CY₃ in Formula 1.

n2 in Formula CY2-1 to CY2-20 has been described based on when n2 hasits maximum value, and n2 may be an integer from 0 to 3, varyingdepending on a corresponding chemical formula. For example, n2 inFormula CY2-1 may be 0, 1, 2, or 3, and n2 in Formula CY2-2 may be 0, 1,or 2.

In one or more embodiments, regarding Formula 1, a moiety represented by

may be a group represented by one of Formulae CY3-1 to CY3-12:

In Formulae CY3-1 to CY3-12,

-   -   X₃, R₃, Z₃, and n3 are the same as described above, and n3 may        be an integer from 0 to 5,    -   X₃₉ may be C(R_(39a))(R_(39b)), N[(L₃₉)_(b39)-(R₃₉)_(c39)], O,        S, or Si(R_(39a))(R_(39b)),    -   L₃₉ may be the same as explained in connection with L₃,    -   b39 and c39 may be the same as described in connection with b3        and c3,    -   R_(39a) and R_(39b) may be the same as described in connection        with R₃,    -   a32 may be an integer from 0 to 2,    -   a33 may be an integer from 0 to 3,    -   a34 may be an integer from 0 to 4,    -   a35 may be an integer from 0 to 5,    -   * indicates a binding site to T₂ in Formula 1,    -   *′ indicates a binding site to M in Formula 1, and    -   *″ indicates a binding site to ring CY₂ in Formula 1.

n3 in Formulae CY3-1 to CY3-12 has been described based on when n3 hasits maximum value, and n3 may be an integer from 0 to 5, varyingdepending on a corresponding chemical formula. For example, n3 inFormula CY3-1 may be 0, 1, 2, or 3, and n3 in Formula CY3-9 may be 0, 1,2, 3, 4, or 5.

In one or more embodiments, regarding Formula 1, a moiety represented by

may be a group represented by one of Formulae CY4-1 to CY4-26:

In Formulae CY4-1 to CY4-26,

-   -   X₄, R₄, Z₄, and n4 may be the same as described above, and n4        may be 0, 1, 2, 3, 4, 5, or 6,    -   X₄₉ may be C(R_(49a))(R_(49b)), N[(L₄₉)_(b49)-(R₄₉)_(c49)], O,        S, or Si(R_(49a))(R_(49b)),    -   L₄₉ may be the same as explained in connection with L₄,    -   b49 and c49 are the same as described in connection with b4 and        c4,    -   R₄₁ to R₄₉, R_(49a), and R_(49b) are the same as described in        connection with R₄,    -   a42 may be an integer from 0 to 2,    -   a43 may be an integer from 0 to 3,    -   a44 may be an integer from 0 to 4,    -   a45 may be an integer from 0 to 5,    -   a46 may be an integer from 0 to 6,    -   * indicates a binding site to T₂ in Formula 1, and    -   *′ indicates a binding site to M in Formula 1.

n4 in Formulae CY4-1 to CY4-26 has been described based on when n4 hasits maximum value, and n4 may be an integer from 0 to 6, varyingdepending on a corresponding chemical formula. For example, n4 inFormula CY4-1 may be 0, 1, 2, 3, or 4, n4 in Formula CY4-2 may be 0, 1,2, or 3, and n4 in Formula CY4-17 may be 0, 1, 2, 3, 4, 5, or 6.

In one or more embodiments, regarding Formula 1,

-   -   a moiety represented by

may be a group represented by one of Formulae CY1(1) to CY1(16) andCY1-d(1) to CY1-d(18), and (or),

-   -   a moiety represented by

may be a group represented by one of Formulae CY2(1) to CY2(20) andCY2-d(1) to CY2-d(15), and (or),

-   -   a moiety represented by

may be a group represented by one of Formulae CY3(1) to CY3(12) andCY3-d(1) to CY3-d(13), and (or),

-   -   a moiety represented by

may be a group represented by one of Formulae CY4(1) to CY4(10) andCY4-d(1) to CY4-d(18), but embodiments are not limited thereto.

In Formulae CY1(1) to CY1 (16), CY1-d(1) to CY1-d(18), CY2(1) toCY2(20), CY2-d(1) to CY2-d(15), CY3(1) to CY3(12), CY3-d(1) toCY3-d(13), CY4(1) to CY4(10), and CY4-d(1) to CY4-d(18),

-   -   X₂ to X₄, Y₁, X₅₁, R₁ to R₄ and Z₁ to Z₄ may be the same as        described above,    -   X₁₉ may be C(R_(19a))(R_(19b)), N[(L₁₉)_(b19)-(R₁₉)_(c19)], O,        S, or Si(R_(19a))(R_(19b)),    -   X₃₉ may be C(R_(39a))(R_(39b)), N[(L₃₉)_(b39)-(R₃₉)_(c39)], O,        S, or Si(R_(39a))(R_(39b)),    -   L₁₉, b19, R₁₉, and c19 are the same as described in connection        with L₁, b1, R₁, and c1, respectively,    -   L₃₉, b39, R₃₉, and c39 are the same as described in connection        with L₃, b3, R₃, and c3, respectively.

R_(1a) to R_(1d), R_(19a), and R_(19b) are the same as described inconnection with R₁,

-   -   R_(3a) to R_(3c), R_(39a), and R_(39b) are the same as described        in connection with R₃,    -   R_(4a) to R_(4d) may be the same as described in connection with        R₄,    -   each of R₁ to R₄, R_(1a) to R_(1d), R_(3a) to R_(3c) and R_(4a)        to R_(4d) is not hydrogen,    -   Z_(1a) to Z_(1d) are the same as described in connection with        Z₁,    -   Z_(3a) to Z_(3c) are the same as described in connection with        Z₃,    -   Z_(4a) to Z_(4d) are the same as described in connection with        Z₄,    -   regarding Formula CY1(1) to CY1(16) and CY1-d(1) to CY1-d(18),        *′ indicates a binding site to X₁ or M in Formula 1, and *        indicates a binding site to T₁ in Formula 1,    -   regarding Formulae CY2(1) to CY2(20) and CY2-d(1) to CY2-d(15),        *′ indicates a binding site to M in Formula 1, * indicates a        binding site to T₁ in Formula 1, and *″ indicates a binding site        to ring CY₃ in Formula 1,    -   regarding Formulae CY3(1) to CY3(12) and CY3-d(1) to CY3-d(13),        *′ indicates a binding site to M in Formula 1, *″ indicates a        binding site to ring CY₂ in Formula 1, and * indicates a binding        site to T₂ in Formula 1, and    -   regarding Formulae CY4(1) to CY4(10) and CY4-d(1) to CY4-d(18),        *′ indicates a binding site to M in Formula 1, and * indicates a        binding site to T₂ in Formula 1.

In an embodiment, each of R₁ to R₄, R_(1a) to R_(1d), R_(3a) to R_(3c)and R_(4a) to R_(4d) in Formulae CY₁(1) to CY₁(16), CY2(1) to CY2(20),CY3(1) to CY3(13) and CY4(1) to CY4(10) may not be deuterium and adeuterium-containing group.

In one or more embodiments, Formula 1 may satisfy at least one ofCondition 1 to Condition 5:

-   -   Condition 1

In Formula 1, a moiety represented by

may be a group represented by one of Formulae CY1-d(1) to CY1-d(18).

-   -   Condition 2

In Formula 1, a moiety represented by

may be a group represented by one of Formulae CY2-d(1) to CY2-d(15).

-   -   Condition 3

In Formula 1, a moiety represented by

is a group represented by one of Formulae CY3-d(1) to CY3-d(13).

-   -   Condition 4

In Formula 1, a moiety represented by

may be a group represented by one of Formulae CY4-d(1) to CY4-d(18).

-   -   Condition 5    -   a) in Formula 1, a moiety represented by

may be a group represented by one of Formulae CY2(1) to CY2(20), and b)regarding Formulae CY2(1) to CY2(20), i) X₅₁ is N-[(L₇)_(b7)-(R₇)_(c7)],C(R₇), Si(R₇), or Ge(R₇), and R₇ is deuterium or a deuterium-containinggroup, or ii) X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), and at leastone of R₇ and R₈ is deuterium or a deuterium-containing group.

Regarding Formula 1, i) two of a plurality of neighboring groups R₁ mayoptionally be linked to each other to form a C₅-C₃₀ carbocyclic groupunsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀heterocyclic group unsubstituted or substituted with at least oneR_(10a), ii) two of a plurality of neighboring groups R₂ may optionallybe linked to each other to form a C₅-C₃₀ carbocyclic group unsubstitutedor substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a), iii) two of aplurality of neighboring groups R₃ may optionally be linked to eachother to form a C₅-C₃₀ carbocyclic group unsubstituted or substitutedwith at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstitutedor substituted with at least one R_(10a), iv) two of a plurality ofneighboring groups R₄ may optionally be linked to each other to form aC₅-C₃₀ carbocyclic group unsubstituted or substituted with at least oneR_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted withat least one R_(10a), and v) two or more neighboring substituentsselected from R₁ to R₄, R₇ to R₁₀, R′ and R″ may optionally be linked toeach other to form a C₅-C₃₀ carbocyclic group unsubstituted orsubstituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic groupunsubstituted or substituted with at least one R_(10a). Herein, theC₅-C₃₀ carbocyclic group and the C₁-C₃₀ heterocyclic group may beunderstood by referring to the descriptions about i) the first ring, ii)the second ring, iii) the condensed ring in which two or more firstrings are condensed with each other, iv) the condensed ring in which twoor more second rings are condensed with each other, and v) the condensedring in which one or more first rings and one or more second rings arecondensed with each other, and R_(10a) may be understood by referring tothe description about R₁.

“An azabenzothiophene, an azabenzofuran, an azaindene, an azaindole, anazabenzosilole, an azadibenzothiophene, an azadibenzofuran, anazafluorene, an azacarbazole, and an azadibenzosilole” may have the samebackbone as those of “a benzothiophene, a benzofuran, an indene, anindole, a benzosilole, a dibenzothiophene, a dibenzofuran, a fluorene, acarbazole, and a dibenzosilole,” respectively, and may each be aheteroring in which at least one of ring-forming carbon atoms issubstituted with nitrogen.

In one embodiment, the organometallic compound represented by Formula 1may be represented by Formula 1A as follows:

In Formula 1A, the descriptions for M, X₁ to X₄, Y₁, X₅₁, L₁ to L₄, b1to b4, R₁ to R₄, c1 to c4, Z₁ to Z₄, a1 to a4 and n1 to n4 may be thesame as described in this disclosure.

For example, the organometallic compound represented by Formula 1 may beone of Compounds 1 to 666 below, but embodiments of the presentdisclosure are not limited thereto.

Z₁ to Z₄ in Formula 1 may each independently be deuterium or adeuterium-containing group, and i) when X₅₁ is O, S, C(═O), or N, thesum of n1 to n4 may be 1 or more, ii) when X₅₁ isN[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or Ge(R₇), a) R₇ is deuterium ora deuterium-containing group; b) the sum of n1 to n4 may be 1 or more;or c) R₇ is deuterium or a deuterium-containing group and the sum of n1to n4 is 1 or more, and iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), orGe(R₇)(R₈), a) at least one of R₇ and R₈ may be deuterium or adeuterium-containing group; b) the sum of n1 to n4 is 1 or more; or c)at least one of R₇ and R₈ is deuterium or a deuterium-containing groupand the sum of n1 to n4 is 1 or more. That is, the organometalliccompound represented by Formula 1 may essentially include at least onedeuterium. Accordingly, the reduced mass of the organometallic compoundrepresented by Formula 1 is changed, and thus, a molecular structurechange caused by energy quenching caused due to vibration of theorganometallic compound being in an excited state is decreased. Due tothe decrease in the molecular structure change, an electronic deviceincluding the organometallic compound represented by Formula 1, forexample, an organic light-emitting device including the organometalliccompound represented by Formula 1 may have improved lifespancharacteristics.

In one or more embodiments, X₂ to X₄ in Formula 1 may each independentlybe N or C, two selected from X₂ to X₄ may each be N, and the remainingone may be C, and a bond between X₁ or Y₁ and M may be a covalent bond,and one bond selected from a bond between X₂ and M, a bond between X₃and M, and a bond between X₄ and M may be a covalent bond, and theremaining two bonds may each be a coordinate bond. In an embodiment, X₂of ring CY₅, X₃ of ring CY₃, and X₄ of ring CY₄ in Formula 1 may notconstitute a carbine moiety. That is, regarding Formula 1, 1) when X₂ isC, a bond between X₂ and M may be a covalent bond, 2) when X₃ is C, abond between X₃ and M may be a covalent bond, and 3) when X₄ is C, abond between X₄ and M may be a covalent bond. Therefore, the structuralchange of the main emission moiety of the organometallic compoundrepresented by Formula 1 in an exited state is decreased, and thus,color purity of an electronic device including the organometalliccompound, for example, an organic light-emitting device including theorganometallic compound may be improved.

Furthermore, each of ring CY₁, ring CY₃, and ring CY₄ in Formula 1 maynot be a benzimidazole group. Accordingly, since the steric hindrance ofa ligand surrounding the center metal M is improved, an electronicdevice including the organometallic compound, for example, an organiclight-emitting device including the organometallic compound may have animproved lifespan characteristic and a sharp electroluminescence peak.

For example, HOMO, LUMO, singlet (S₁) and triplet (T₁) energy levels ofCompounds 1 to 10 and 13 were evaluated by using a DFT method ofGaussian program (structurally optimized at a level of B3LYP,6-31G(d,p)). Evaluation results are shown in Table 1 below.

TABLE 1 HOMO LUMO Energy gap S₁ energy T₁ energy Compound No. (eV) (eV)(eV) level (eV) level (eV) 1 −4.85 −1.546 3.304 2.751 2.517 2 −4.85−1.546 3.304 2.751 2.517 3 −4.85 −1.546 3.304 2.751 2.517 4 −4.869−1.589 3.280 2.728 2.472 5 −4.869 −1.589 3.280 2.728 2.472 6 −4.869−1.589 3.280 2.728 2.472 7 −4.994 −1.793 3.201 2.661 2.439 8 −4.994−1.793 3.201 2.661 2.439 9 −4.994 −1.793 3.201 2.661 2.439 10 −4.794−1.528 3.266 2.721 2.47 13 −4.782 −1.528 3.254 2.719 2.466

From Table 1, it is confirmed that the organometallic compoundrepresented by Formula 1 has such electric characteristics that aresuitable for use as a dopant for an electronic device, for example, anorganic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula1 may be recognizable by one of ordinary skill in the art by referringto Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for usein an organic layer of an organic light-emitting device, for example,for use as a dopant in an emission layer of the organic layer. Thus,another aspect provides an organic light-emitting device that includes:a first electrode; a second electrode; and an organic layer that islocated between the first electrode and the second electrode, whereinthe organic layer includes an emission layer and at least oneorganometallic compound represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of anorganic layer including the organometallic compound represented byFormula 1, a low driving voltage, high efficiency, high powerefficiency, high quantum efficiency, a long lifespan, a low roll-offratio, and excellent color purity.

The organometallic compound of Formula 1 may be used between a pair ofelectrodes of an organic light-emitting device. For example, theorganometallic compound represented by Formula 1 may be included in theemission layer. In this regard, the organometallic compound may act as adopant, and the emission layer may further include a host (that is, anamount of the organometallic compound represented by Formula 1 issmaller than an amount of the host).

The expression “(an organic layer) includes at least one organometalliccompounds” as used herein may include an embodiment in which “(anorganic layer) includes identical organometallic compounds representedby Formula 1” and an embodiment in which “(an organic layer) includestwo or more different organometallic compounds represented by Formula1.”

For example, the organic layer may include, as the organometalliccompound, only Compound 1. In this regard, Compound 1 may be included inan emission layer of the organic light-emitting device. In one or moreembodiments, the organic layer may include, as the organometalliccompound, Compound 1 and Compound 2. In this regard, Compound 1 andCompound 2 may be included in an identical layer (for example, Compound1 and Compound 2 may all be included in an emission layer).

The first electrode may be an anode, which is a hole injectionelectrode, and the second electrode may be a cathode, which is anelectron injection electrode; or the first electrode may be a cathode,which is an electron injection electrode, and the second electrode maybe an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the firstelectrode is an anode, and the second electrode is a cathode, and theorganic layer further includes a hole transport region disposed betweenthe first electrode and the emission layer and an electron transportregion disposed between the emission layer and the second electrode,wherein the hole transport region includes a hole injection layer, ahole transport layer, an electron blocking layer, or any combinationthereof, and the electron transport region includes a hole blockinglayer, an electron transport layer, an electron injection layer, or anycombination thereof.

The term “organic layer” as used herein refers to a single layer and/ora plurality of layers disposed between the first electrode and thesecond electrode of the organic light-emitting device. The “organiclayer” may include, in addition to an organic compound, anorganometallic complex including metal.

The FIGURE a schematic view of an organic light-emitting device 10according to an embodiment. Hereinafter, the structure of an organiclight-emitting device according to an embodiment and a method ofmanufacturing an organic light-emitting device according to anembodiment will be described in connection with the FIGURE. The organiclight-emitting device 10 includes a first electrode 11, an organic layer15, and a second electrode 19, which are sequentially stacked.

A substrate may be additionally located under the first electrode 11 orabove the second electrode 19. For use as the substrate, any substratethat is used in general organic light-emitting devices may be used, andthe substrate may be a glass substrate or a transparent plasticsubstrate, each having excellent mechanical strength, thermal stability,transparency, surface smoothness, ease of handling, and waterresistance.

In one or more embodiments, the first electrode 11 may be formed bydepositing or sputtering a material for forming the first electrode 11on the substrate. The first electrode 11 may be an anode. The materialfor forming the first electrode 11 may be selected from materials with ahigh work function to facilitate hole injection. The first electrode 11may be a reflective electrode, a semi-transmissive electrode, or atransmissive electrode. The material for forming the first electrode 11may be indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide(SnO₂), or zinc oxide (ZnO). In one or more embodiments, the materialfor forming the first electrode 11 may be metal, such as magnesium (Mg),aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium(Mg—In), or magnesium-silver (Mg—Ag).

The first electrode 11 may have a single-layered structure or amulti-layered structure including two or more layers. For example, thefirst electrode 11 may have a three-layered structure of ITO/Ag/ITO, butthe structure of the first electrode 11 is not limited thereto.

The organic layer 15 is located on the first electrode 11.

The organic layer 15 may include a hole transport region, an emissionlayer, and an electron transport region.

The hole transport region may be between the first electrode 11 and theemission layer.

The hole transport region may include a hole injection layer, a holetransport layer, an electron blocking layer, a buffer layer, or anycombination thereof.

The hole transport region may include only either a hole injection layeror a hole transport layer. In one or more embodiments, the holetransport region may have a hole injection layer/hole transport layerstructure or a hole injection layer/hole transport layer/electronblocking layer structure, which are sequentially stacked in this statedorder from the first electrode 11.

When the hole transport region includes a hole injection layer (HIL),the hole injection layer may be formed on the first electrode 11 byusing one or more suitable methods, for example, vacuum deposition, spincoating, casting, and/or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, thedeposition conditions may vary according to a material that is used toform the hole injection layer, and the structure and thermalcharacteristics of the hole injection layer. For example, the depositionconditions may include a deposition temperature of about 100 to about500° C., a vacuum pressure of about 10⁻⁸ torr to about 10⁻³ torr, and adeposition rate of about 0.01 Angstroms per second (A/sec) to about 100Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coatingconditions may vary according to the material used to form the holeinjection layer, and the structure and thermal properties of the holeinjection layer. For example, a coating speed may be from about 2,000revolutions per minute (rpm) to about 5,000 rpm, and a temperature atwhich a heat treatment is performed to remove a solvent after coatingmay be from about 80° C. to about 200° C. However, the coatingconditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blockinglayer may be understood by referring to conditions for forming the holeinjection layer.

The hole transport region may include at least one selected fromm-MTDATA, TDATA, 2-TNATA, NPB, R-NPB, TPD, Spiro-TPD, Spiro-NPB,methylated-NPB, TAPC, HMTPD, 4,4′,4″-tris(N-carbazolyl)triphenylamine(TCTA), polyaniline/dodecylbenzene sulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(4-styrenesulfonate) (PANI/PSS), a compound represented by Formula 201 below, anda compound represented by Formula 202 below:

Ar₁₀₁ to Ar₁₀₂ in Formula 201 may each independently be selected from

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anacenaphthylene group, a fluorenylene group, a phenalenylene group, aphenanthrenylene group, an anthracenylene group, a fluoranthenylenegroup, a triphenylenylene group, a pyrenylene group, a chrysenylenylenegroup, a naphthacenylene group, a picenylene group, a perylenylenegroup, and a pentacenylene group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyanogroup, a nitro group, an amino group, an amidino group, a hydrazinegroup, a hydrazone group, a carboxylic acid group or a salt thereof, asulfonic acid group or a salt thereof, a phosphoric acid group or a saltthereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

xa and xb in Formula 201 may each independently be an integer from 0 to5, or 0, 1 or 2. For example, xa may be 1 and xb may be 0, but xa and xbare not limited thereto.

R₁₀₁ to R₁₀₈, R₁₁₁ to R₁₁₉ and R₁₂₁ to R₁₂₄ in Formulae 201 and 202 mayeach independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group (for example, a methyl group, an ethyl group, apropyl group, a butyl group, a pentyl group, a hexyl group, and so on),or a C₁-C₁₀ alkoxy group (for example, a methoxy group, an ethoxy group,a propoxy group, a butoxy group, a pentoxy group, and so on);

a C₁-C₁₀ alkyl group or a C₁-C₁₀ alkoxy group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, and a phosphoric acidgroup or a salt thereof;

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, or a pyrenyl group; and

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenylgroup, and a pyrenyl group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amino group, an amidino group, a hydrazine group, ahydrazone group, a carboxylic acid group or a salt thereof, a sulfonicacid group or a salt thereof, a phosphoric acid group or a salt thereof,a C₁-C₁₀ alkyl group, and a C₁-C₁₀ alkoxy group,

but embodiments of the present disclosure are not limited thereto.

R₁₀₉ in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup; and

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinylgroup, each substituted with at least one selected from a deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an aminogroup, an amidino group, a hydrazine group, a hydrazone group, acarboxylic acid or a salt thereof, a sulfonic acid or a salt thereof, aphosphoric acid or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxygroup, a phenyl group, a naphthyl group, an anthracenyl group, and apyridinyl group.

According to an embodiment, the compound represented by Formula 201 maybe represented by Formula 201A below, but embodiments of the presentdisclosure are not limited thereto:

R₁₀₁, R₁₁₁, R₁₁₂, and R₁₀₉ in Formula 201A may be understood byreferring to the description provided herein.

For example, the compound represented by Formula 201, and the compoundrepresented by Formula 202 may include compounds HT1 to HT20 illustratedbelow, but are not limited thereto:

A thickness of the hole transport region may be in a range of about 100Å to about 10,000 Å, for example, about 100 Å to about 1,000 Å. When thehole transport region includes at least one of a hole injection layerand a hole transport layer, a thickness of the hole injection layer maybe in a range of about 100 Å to about 10,000 Å, for example, about 100 Åto about 1,000 Å, and a thickness of the hole transport layer may be ina range of about 50 Å to about 2,000 Å, for example about 100 Å to about1,500 Å. While not wishing to be bound by theory, it is understood thatwhen the thicknesses of the hole transport region, the hole injectionlayer and the hole transport layer are within these ranges, satisfactoryhole transporting characteristics may be obtained without a substantialincrease in driving voltage.

The hole transport region may further include, in addition to thesematerials, a charge-generation material for the improvement ofconductive properties. The charge-generation material may behomogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant. Thep-dopant may be one selected from a quinone derivative, a metal oxide,and a cyano group-containing compound, but embodiments of the presentdisclosure are not limited thereto. Non-limiting examples of thep-dopant are a quinone derivative, such as tetracyanoquinonedimethane(TCNQ) or 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane(F4-TCNQ); a metal oxide, such as a tungsten oxide or a molybdeniumoxide; and a cyano group-containing compound, such as Compound HT-D1below, but are not limited thereto.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distanceaccording to a wavelength of light emitted from the emission layer, andthus, efficiency of a formed organic light-emitting device may beimproved.

Then, an emission layer (EML) may be formed on the hole transport regionby vacuum deposition, spin coating, casting, LB deposition, or the like.When the emission layer is formed by vacuum deposition or spin coating,the deposition or coating conditions may be similar to those applied informing the hole injection layer although the deposition or coatingconditions may vary according to a material that is used to form thehole transport layer.

Meanwhile, when the hole transport region includes an electron blockinglayer, a material for the electron blocking layer may be selected frommaterials for the hole transport region described above and materialsfor a host to be explained later. However, the material for the electronblocking layer is not limited thereto. For example, when the holetransport region includes an electron blocking layer, a material for theelectron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant mayinclude the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (alsoreferred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and CompoundH51:

In one or more embodiments, the host may further include a compoundrepresented by Formula 301 below.

Ar₁₁₁ and Ar₁₁₂ in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and apyrenylene group, each substituted with at least one selected from aphenyl group, a naphthyl group, and an anthracenyl group.

Ar₁₁₃ to Ar₁₁₆ in Formula 301 may each independently be selected from:

a C₁-C₁₀ alkyl group, a phenyl group, a naphthyl group, a phenanthrenylgroup, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenylgroup, each substituted with at least one selected from a phenyl group,a naphthyl group, and an anthracenyl group.

g, h, i, and j in Formula 301 may each independently be an integer from0 to 4, and may be, for example, 0, 1, or 2.

Ar₁₁₃ and Ar₁₁₆ in Formula 301 may each independently be selected from

a C₁-C₁₀ alkyl group, substituted with at least one selected from aphenyl group, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl, aphenanthrenyl group, and a fluorenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group,a phenanthrenyl group, and a fluorenyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amino group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a phenyl group, a naphthylgroup, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, anda fluorenyl group; and

but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, the host may include a compound representedby Formula 302 below:

Ar₁₂₂ to Ar₁₂₅ in Formula 302 are the same as described in detail inconnection with Ar₁₁₃ in Formula 301.

Ar₁₂₆ and Ar₁₂₇ in Formula 302 may each independently be a C₁-C₁₀ alkylgroup (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4.For example, k and l may be 0, 1, or 2.

When the organic light-emitting device is a full-color organiclight-emitting device, the emission layer may be patterned into a redemission layer, a green emission layer, and a blue emission layer. Inone or more embodiments, due to a stacked structure including a redemission layer, a green emission layer, and/or a blue emission layer,the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of thedopant may be in a range of about 0.01 parts by weight to about 15 partsby weight based on 100 parts by weight of the host, but embodiments ofthe present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å toabout 1,000 Å, for example, about 200 Å to about 600 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the emission layer is within this range, excellent light-emissioncharacteristics may be obtained without a substantial increase indriving voltage.

Then, an electron transport region may be located on the emission layer.

The electron transport region may include a hole blocking layer, anelectron transport layer, an electron injection layer, or anycombination thereof.

For example, the electron transport region may have a hole blockinglayer/electron transport layer/electron injection layer structure or anelectron transport layer/electron injection layer structure, but thestructure of the electron transport region is not limited thereto. Theelectron transport layer may have a single-layered structure or amulti-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transportlayer, and the electron injection layer which constitute the electrontransport region may be understood by referring to the conditions forforming the hole injection layer.

When the electron transport region includes a hole blocking layer, thehole blocking layer may include, for example, at least one of BCP,BPhen, and BAlq but embodiments of the present disclosure are notlimited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Åto about 1,000 Å, for example, about 30 Å to about 300 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the hole blocking layer is within these ranges, the hole blockinglayer may have excellent hole blocking characteristics without asubstantial increase in driving voltage.

The electron transport layer may further include at least one selectedfrom BCP, BPhen, Alq₃, BAlq, TAZ, and NTAZ.

In one or more embodiments, the electron transport layer may include atleast one of ET1 to ET25, but are not limited thereto:

A thickness of the electron transport layer may be in a range of about100 Å to about 1,000 Å, for example, about 150 Å to about 500 Å. Whilenot wishing to be bound by theory, it is understood that when thethickness of the electron transport layer is within the range describedabove, the electron transport layer may have satisfactory electrontransport characteristics without a substantial increase in drivingvoltage.

Also, the electron transport layer may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include a Li complex. The Li complexmay include, for example, Compound ET-D1 (lithium 8-hydroxyquinolate,LiQ) or ET-D2.

The electron transport region may include an electron injection layer(EIL) that promotes flow of electrons from the second electrode 19thereinto.

The electron injection layer may include at least one selected from LiF,NaCl, CsF, Li₂O, and BaO.

A thickness of the electron injection layer may be in a range of about 1Å to about 100 Å, and, for example, about 3 Å to about 90 Å. While notwishing to be bound by theory, it is understood that when the thicknessof the electron injection layer is within the range described above, theelectron injection layer may have satisfactory electron injectioncharacteristics without a substantial increase in driving voltage.

The second electrode 19 is located on the organic layer 15. The secondelectrode 19 may be a cathode. A material for forming the secondelectrode 19 may be metal, an alloy, an electrically conductivecompound, or a combination thereof, which have a relatively low workfunction. For example, lithium (Li), magnesium (Mg), aluminum (Al),aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), ormagnesium-silver (Mg—Ag) may be formed as the material for forming thesecond electrode 19. To manufacture a top-emission type light-emittingdevice, a transmissive electrode formed using ITO or IZO may be used asthe second electrode 19.

Hereinbefore, the organic light-emitting device has been described withreference to the FIGURE, but embodiments of the present disclosure arenot limited thereto.

Another aspect provides a diagnostic composition including at least oneorganometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides highluminescent efficiency. Accordingly, a diagnostic composition includingthe organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications includinga diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched saturated aliphatic hydrocarbon monovalent group having 1 to 60carbon atoms, and non-limiting examples thereof include a methyl group,an ethyl group, a propyl group, an iso-butyl group, a sec-butyl group, atert-butyl group, a pentyl group, an iso-amyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having the same structure as that of the C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by —OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group),and examples thereof include a methoxy group, an ethoxy group, and aniso-propyloxy group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon double bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group, and examplesthereof include an ethenyl group, a propenyl group, and a butenyl group.The term “C₂-C₆₀ alkenylene group” as used herein refers to a divalentgroup having the same structure as that of the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup formed by including at least one carbon-carbon triple bond in themiddle or at the terminus of the C₂-C₆₀ alkyl group, and examplesthereof include an ethynyl group, and a propynyl group. The term “C₂-C₆₀alkynylene group” as used herein refers to a divalent group having thesame structure as that of the C₂-C₆₀ alkynyl group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, andexamples thereof include a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term“C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent grouphaving the same structure as that of the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁ o heterocycloalkyl group” as used herein refers to amonovalent saturated monocyclic group having at least one heteroatomselected from N, O, P, Si and S as a ring-forming atom and 1 to 10carbon atoms, and non-limiting examples thereof include atetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalentgroup having the same structure as the C₁-C₁₀ heterocycloalkyl group.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in the ring thereof and no aromaticity,and non-limiting examples thereof include a cyclopentenyl group, acyclohexenyl group, and a cycloheptenyl group. The term “C₃-C₁₀cycloalkenylene group” as used herein refers to a divalent group havingthe same structure as the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, P, Si, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one double bond in its ring. Examples of the C₁-C₁₀heterocycloalkenyl group are a 2,3-dihydrofuranyl group, and a2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having the samestructure as the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, andthe term “C₆-C₆₀ arylene group” as used herein refers to a divalentgroup having a carbocyclic aromatic system having 6 to 60 carbon atoms.Non-limiting examples of the C₆-C₆₀ aryl group include a phenyl group, anaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, and a chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀arylene group each include two or more rings, the rings may be fused toeach other. The C₇-C₆₀ alkylaryl group refers to a C₆-C₆₀ aryl groupsubstituted with at least one C₁-C₆₀ alkyl group.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a heterocyclic aromatic system that has at least oneheteroatom selected from N, O, P, Si, and S as a ring-forming atom, and1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group” as usedherein refers to a divalent group having a heterocyclic aromatic systemthat has at least one heteroatom selected from N, O, P, and S as aring-forming atom, and 1 to 60 carbon atoms. Examples of the C₁-C₆₀heteroaryl group include a pyridinyl group, a pyrimidinyl group, apyrazinyl group, a pyridazinyl group, a triazinyl group, a quinolinylgroup, and an isoquinolinyl group. When the C₆-C₆₀ heteroaryl group andthe C₆-C₆₀ heteroarylene group each include two or more rings, the ringsmay be fused to each other. The C₂-C₆₀ alkylheteroaryl group refers to aC₁-C₆₀ heteroaryl group substituted with at least one C₁-C₆₀ alkylgroup.

The term “C₆-C₆₀ aryloxy group” as used herein indicates —OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), the term “C₆-C₆₀ arylthio group” as usedherein indicates —SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group), and theterm “C₇-C₆₀ aryl alkyl group” as used herein indicates -A₁₀₄A₁₀₅(wherein A₁₀₅ is the C₆-C₅₉ aryl group and A₁₀₄ is the C₁-C₅₃ alkylenegroup).

The term “C₁-C₆₀ heteroaryloxy group” as used herein refers to —OA₁₀₆(wherein A₁₀₆ is the C₂-C₆₀ heteroaryl group), the term “C₁-C₆₀heteroarylthio group” as used herein indicates —SA₁₀₇ (wherein A₁₀₇ isthe C₁-C₆₀ heteroaryl group), and the term “C₂-C₆₀ heteroarylalkylgroup” as used herein refers to -A₁₀₈A₁₀₉ (A₁₀₉ is a C₁-C₅₉ heteroarylgroup, and A₁₀₈ is a C₁-C₅₉ alkylene group).

The term “monovalent non-aromatic condensed polycyclic group” as usedherein refers to a monovalent group (for example, having 8 to 60 carbonatoms) having two or more rings condensed to each other, only carbonatoms as ring-forming atoms, and no aromaticity in its entire molecularstructure. Examples of the monovalent non-aromatic condensed polycyclicgroup include a fluorenyl group. The term “divalent non-aromaticcondensed polycyclic group” as used herein refers to a divalent grouphaving the same structure as the monovalent non-aromatic condensedpolycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” asused herein refers to a monovalent group (for example, having 2 to 60carbon atoms) having two or more rings condensed to each other, aheteroatom selected from N, O, P, Si, and S, other than carbon atoms, asa ring-forming atom, and no aromaticity in its entire molecularstructure. Non-limiting examples of the monovalent non-aromaticcondensed heteropolycyclic group include a carbazolyl group. The term“divalent non-aromatic condensed heteropolycyclic group” as used hereinrefers to a divalent group having the same structure as the monovalentnon-aromatic condensed heteropolycyclic group.

The term “C₅-C₃₀ carbocyclic group” as used herein refers to a saturatedor unsaturated cyclic group having, as a ring-forming atom, 5 to 30carbon atoms only. The C₅-C₃₀ carbocyclic group may be a monocyclicgroup or a polycyclic group.

The term “C₁-C₃₀ heterocyclic group” as used herein refers to asaturated or unsaturated cyclic group having, as a ring-forming atom, atleast one heteroatom selected from N, O, Si, P, and S other than 1 to 30carbon atoms. The C₁-C₃₀ heterocyclic group may be a monocyclic group ora polycyclic group.

at least one of substituents of the substituted C₅-C₃₀ carbocyclicgroup, substituted C₁-C₃₀ heterocyclic group, substituted C₁-C₆₀ alkylgroup, substituted C₂-C₆₀ alkenyl group, substituted C₂-C₆₀ alkynylgroup, substituted C₁-C₆₀ alkoxy group, substituted C₃-C₁₀ cycloalkylgroup, substituted C₁-C₁₀ heterocycloalkyl group, substituted C₃-C₁₀cycloalkenyl group, substituted C₁-C₁₀ heterocycloalkenyl group,substituted C₆-C₆₀ aryl group, substituted C₇-C₆₀ alkylaryl group,substituted C₆-C₆₀ aryloxy group, substituted C₆-C₆₀ arylthio group,substituted C₇-C₆₀ arylalkyl group, substituted C₁-C₆₀ heteroaryl group,substituted C₁-C₆₀ heteroaryloxy group, substituted C₁-C₆₀heteroarylthio group, substituted C₂-C₆₀ heteroarylalkyl group,substituted C₂-C₆₀ alkylheteroaryl group, substituted monovalentnon-aromatic condensed polycyclic group, and substituted monovalentnon-aromatic condensed heteropolycyclic group is selected from:

deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H,—CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group,a hydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group,a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkylgroup, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀alkylheteroaryl group, a monovalent non-aromatic condensed polycyclicgroup, a monovalent non-aromatic condensed heteropolycyclic group,—N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group, each substituted with at least oneselected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃,—CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazine group, a hydrazone group, a carboxylic acid group ora salt thereof, a sulfonic acid group or a salt thereof, a phosphoricacid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenylgroup, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, a monovalent non-aromaticcondensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅),—B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and

—N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉);

wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ may eachindependently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazine group, a hydrazone group, a carboxylic acid group or a saltthereof, a sulfonic acid group or a salt thereof, a phosphoric acidgroup or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynylgroup, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl groupsubstituted with at least one selected from deuterium, a C₁-C₆₀ alkylgroup, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalentnon-aromatic condensed polycyclic group, and a monovalent non-aromaticcondensed heteropolycyclic group.

Hereinafter, a compound and an organic light-emitting device accordingto embodiments are described in detail with reference to SynthesisExample and Examples. However, the organic light-emitting device is notlimited thereto. The wording “B was used instead of A” used indescribing Synthesis Examples means that an amount of A used wasidentical to an amount of B used, in terms of a molar equivalent.

EXAMPLES Synthesis Example 1: Synthesis of Compound 3

Synthesis of Intermediate 3-C

2 grams (g) (6.60 millimoles, mmol) of starting material 3-A, 2.53 g(7.26 mmol, 1.1 equivalents, equiv.) of starting material 3-B, 0.53 g(0.46 mmol, 0.07 equiv.) of tetrakis(triphenylphosphine)palladium (0)),and 2.74 g (19.79 mmol, 3 equiv.) of potassium carbonate were mixed with48 mL of a mixture including tetrahydrofuran (THF) and H₂O at a ratio of3:1, and the resulting mixture was refluxed overnight. The obtainedresultant was cooled to room temperature, and the precipitate wasremoved therefrom to obtain a filtrate. The filtrate was washed withethylene acetate (EA)/H₂O, and purified by column chromatography toproduce 1.7 g (yield of 78%) of Intermediate 3-C. The obtained compoundwas identified by LC-MS.

LC-MS m/z=444.28 (M+H)⁺

Synthesis of Compound 3

1.5 g (3.37 mmol) of Intermediate 3-C and 1.68 g (4.05 mmol, 1.2 equiv.)of K₂PtCl₄ were mixed with a mixture including 80 mL of AcOH (aceticacid) and 4 mL of H₂O, and then the resulting mixture was refluxedovernight. The obtained resultant was cooled to room temperature andfiltered to obtain the precipitate, which was then mixed with methylenechloride (MC) and washed with H₂O, and purified by column chromatographyto produce 1.1 g (yield 51%) of Compound 3. The obtained compound wasidentified by LC-MS.

LC-MS m/z=637.23 (M+H)⁺

Synthesis Example 2: Synthesis of Compound 17

Synthesis of Intermediate 17-C

2 g (4.19 mmol) of starting material 17-A, 1.93 g (4.61 mmol, 1.1equiv.) of starting material 17-B, 0.34 g (0.29 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium (0), and 1.74 g (12.57 mmol, 3equiv.) of potassium carbonate were mixed with 30 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resulting mixture wasrefluxed overnight. The obtained resultant was cooled to roomtemperature, and the precipitate was removed therefrom to obtain afiltrate. The filtrate was washed with EA/H₂O, and purified by columnchromatography to produce 1.9 g (yield 66%) of Intermediate 17-C. Theobtained compound was identified by LC-MS.

LC-MS m/z=688.42 (M+H)

Synthesis of Compound 17

1.8 g (2.61 mmol) of Intermediate 17-C and 1.3 g (3.14 mmol, 1.2 equiv.)of K₂PtCl₄ were mixed with a mixture including 65 mL of AcOH and 3 mL ofH₂O, and the resulting mixture was refluxed overnight. The obtainedresultant was cooled to room temperature and filtered to obtain theprecipitate, which was then mixed with MC and washed with H₂O, andpurified by column chromatography to produce 1.41 g (yield of 61%) ofCompound 17. The obtained compound was identified by LC-MS.

LC-MS m/z=881.37 (M+H)⁺

Synthesis Example 3: Synthesis of Compound 24

Synthesis of Intermediate 24-C

2 g (3.75 mmol) of starting material 24-A, 1.73 g (4.12 mmol, 1.1equiv.) of starting material 24-B, 0.30 g (0.26 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium (0), and 1.82 g (11.25 mmol, 3equiv.) of potassium carbonate were mixed with 27 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resulting mixture wasrefluxed overnight. The obtained resultant was cooled to roomtemperature, and the precipitate was removed therefrom to obtain afiltrate. The filtrate was washed with EA/H₂O, and purified by columnchromatography to produce 1.9 g (yield 68%) of Intermediate 24-C. Theobtained compound was identified by LC-MS.

LC-MS m/z=744.48 (M+H)⁺

Synthesis of Compound 24

1.7 g (2.28 mmol) of Intermediate 24-C and 1.3 g (3.14 mmol, 1.2 equiv.)of K₂PtCl₄ were mixed with a mixture including 57 mL of AcOH and 3 mL ofH₂O, and the resulting mixture was refluxed overnight. The obtainedresultant was cooled to room temperature and filtered to obtain theprecipitate, which was then mixed with MC and washed with H₂O, andpurified by column chromatography to produce 1.41 g (yield of 65%) ofCompound 24. The obtained compound was identified by LC-MS.

LC-MS m/z=937.43 (M+H)⁺

Synthesis Example 4: Synthesis of Compound 27

Synthesis of Intermediate 27-C

2 g (3.39 mmol) of starting material 27-A, 1.84 g (3.73 mmol, 1.1equiv.) of starting material 27-B, 0.27 g (0.24 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium (0), and 1.41 g (10.18 mmol, 3equiv.) of potassium carbonate were mixed with 27 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resulting mixture wasrefluxed overnight. The obtained resultant was cooled to roomtemperature, and the precipitate was removed therefrom to obtain afiltrate. The filtrate was washed with EA/H₂O, and purified by columnchromatography to produce 2.2 g (yield of 74%) of Intermediate 27-C. Theobtained compound was identified by LC-MS.

LC-MS m/z=875.57 (M+H)⁺

Synthesis of Compound 27

1.5 g (1.71 mmol) of Intermediate 27-C and 0.85 g (3.14 mmol, 1.2equiv.) of K₂PtCl₄ were mixed with a mixture including 43 mL of AcOH and2 mL of H₂O, and the resulting mixture was refluxed overnight. Theobtained resultant was cooled to room temperature and filtered to obtainthe precipitate, which was then mixed with MC and washed with H₂O, andpurified by column chromatography to produce 1.1 g (yield of 60%) ofCompound 27. The obtained compound was identified by LC-MS.

LC-MS m/z=1068.52 (M+H)⁺

Synthesis Example 5: Synthesis of Compound 31

Synthesis of Intermediate 31-C

2 g (3.58 mmol) of starting material 31-A, 1.65 g (3.73 mmol, 1.1equiv.) of starting material 31-B, 0.29 g (0.25 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium (0), and 1.48 g (10.74 mmol, 3equiv.) of potassium carbonate were mixed with 26 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resulting mixture wasrefluxed overnight. The obtained resultant was cooled to roomtemperature, and the precipitate was removed therefrom to obtain afiltrate. The filtrate was washed with EA/H₂O, and purified by columnchromatography to produce 1.8 g (yield of 65%) of Intermediate 31-C. Theobtained compound was identified by LC-MS.

LC-MS m/z=769.48 (M+H)⁺

Synthesis of Compound 31

1.7 g (2.21 mmol) of Intermediate 31-C and 1.1 g (2.65 mmol, 1.2 equiv.)of K₂PtCl₄ were mixed with a mixture including 55 mL of AcOH and 3 mL ofH₂O, and the resulting mixture was refluxed overnight. The obtainedresultant was cooled to room temperature and filtered to obtain theprecipitate, which was then mixed with MC and washed with H₂O, andpurified by column chromatography to produce 1.2 g (yield of 56%) ofCompound 31. The obtained compound was identified by LC-MS.

LC-MS m/z=962.43 (M+H)⁺

Synthesis Example 6: Synthesis of Compound 99

Synthesis of Intermediate 99-C

2 g (3.28 mmol) of starting material 99-A, 1.52 g (3.61 mmol, 1.1equiv.) of starting material 99-B, 0.27 g (0.23 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium(0), and 1.36 g (9.84 mmol, 3equiv.) of potassium carbonate were mixed with 36 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resultant mixture wasrefluxed overnight. The obtained result was cooled to room temperature,and then, the precipitate was removed therefrom to obtain a filtrate.The filtrate was washed with EA/H₂O, and column chromatography wasperformed thereon to complete the production of 2.1 g (yield of 78%) ofIntermediate 99-C. The obtained compound was identified by LC-MS.

LC-MS m/z=824.54 (M+H)⁺

Synthesis of Compound 99

2 g (2.42 mmol) of Intermediate 99-C and 1.21 g (2.91 mmol, 1.2 equiv.)of K₂PtCl₄ were mixed with a mixture including 61 mL of AcOH and 3 mL ofH₂O, and the resultant mixture was refluxed overnight. The obtainedresult was cooled to room temperature and filtered to obtain theprecipitate, which was then mixed with MC and washed with H₂O, andcolumn chromatography was performed thereon to complete the productionof 1.3 g (yield of 53%) of Compound 99. The obtained compound wasidentified by LC-MS.

LC-MS m/z=1017.49 (M+H)⁺

Synthesis Example 7: Synthesis of Compound 157

Synthesis of Intermediate 157-C

2 g (3.5 mmol) of starting material 157-A, 1.64 g (3.85 mmol, 1.1equiv.) of starting material 157-B, 0.28 g (0.24 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium(0), and 1.45 g (10.50 mmol, 3equiv.) of potassium carbonate were mixed with 38 mL of a mixtureincluding THE and H₂O at a ratio of 3:1, and the resultant mixture wasrefluxed overnight. The obtained result was cooled to room temperature,and then, the precipitate was removed therefrom to obtain a filtrate.The filtrate was washed with EA/H₂O, and column chromatography wasperformed thereon to complete the production of 2.1 g (yield of 76%) ofIntermediate 157-C. The obtained compound was identified by LC-MS.

LC-MS m/z=791.55 (M+H)⁺

Synthesis of Compound 157

2 g (2.52 mmol) of Intermediate 157-C 1.26 g (3.03 mmol, 1.2 equiv.) ofK₂PtCl₄ were mixed with a mixture including 63 mL of AcOH and 3 mL ofH₂O, and the resultant mixture was refluxed overnight. The obtainedresult was cooled to room temperature and filtered to obtain theprecipitate, which was then mixed with MC and washed with H₂O, andcolumn chromatography was performed thereon to complete the productionof 1.2 g (yield of 48%) of Compound 157. The obtained compound wasidentified by LC-MS.

LC-MS m/z=984.50 (M+H)⁺

Synthesis Example 8: Synthesis of Compound 186

Synthesis of Intermediate 186-C

2 g (3.61 mmol) of starting material 186-A, 1.73 g (3.97 mmol, 1.1equiv.) of starting material 186-B, 0.29 g (0.25 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium(0), and 1.50 g (10.84 mmol, 3equiv.) of potassium carbonate were mixed with a mixture including THFand H₂O at a ratio of 3:1, and the resultant mixture was refluxedovernight. The obtained result was cooled to room temperature, and then,the precipitate was removed therefrom to obtain a filtrate. The filtratewas washed with EA/H₂O, and column chromatography was performed thereonto complete the production of 1.8 g (yield of 64%) of Intermediate186-C. The obtained compound was identified by LC-MS.

LC-MS m/z=780.48 (M+H)⁺

Synthesis of Compound 186

1.5 g (1.92 mmol) of Intermediate 186-C and 0.96 g (2.3 mmol, 1.2equiv.) of K₂PtCl₄ were mixed with a mixture including 48 mL of AcOH and3 mL of H₂O, and the resultant mixture was refluxed overnight. Theobtained result was cooled to room temperature and filtered to obtainthe precipitate, which was then mixed with MC and washed with H₂O, andcolumn chromatography was performed thereon to complete the productionof 0.8 g (yield of 43%) of Compound 186. The obtained compound wasidentified by LC-MS.

LC-MS m/z=973.43 (M+H)⁺

Synthesis Example 9: Synthesis of Compound 448

Synthesis of Intermediate 448-C

2 g (3.51 mmol) of starting material 448-A, 1.89 g (3.86 mmol, 1.1equiv.) of starting material 448-B, 0.28 g (0.25 mmol, 0.07 equiv.) oftetrakis(triphenylphosphine)palladium(0), and 1.45 g (10.52 mmol, 3equiv.) of potassium carbonate were mixed with 38 mL of a mixtureincluding THF and H₂O at a ratio of 3:1, and the resultant was refluxedovernight. The obtained result was cooled to room temperature, and then,the precipitate was removed therefrom to obtain a filtrate. The filtratewas washed with EA/H₂O, and column chromatography was performed thereonto complete the production of 2.0 g (yield of 73%) of Intermediate448-C. The obtained compound was identified by LC-MS.

LC-MS m/z=852.48 (M+H)⁺

Synthesis of Compound 448

1.8 g (2.11 mmol) of Intermediate 448-C and 1.05 g (2.53 mmol, 1.2equiv.) of K₂PtCl₄ were mixed with a mixture including 53 mL of AcOH and3 mL of H₂O, and the resultant mixture was refluxed overnight. Theobtained result was cooled to room temperature and filtered to obtainthe precipitate, which was then mixed with MC and washed with H₂O, andcolumn chromatography was performed thereon to complete the productionof 1.1 g (yield of 50%) of Compound 448. The obtained compound wasidentified by LC-MS.

LC-MS m/z=1045.43 (M+H)⁺

Evaluation Example 1: Evaluation of Photoluminescence Quantum Yields(PLQY)

PMMA in CH₂Cl₂ solution, 5 percent by weight (wt %) of CBP, and Compound3 were mixed, and the resultant was coated on a quartz substrate byusing a spin coater, and then, heat-treated in an oven at a temperatureof 80° C., and cooled to room temperature to obtain a film.

The PLQY of Compound 3 in film was evaluated by using a HamamatsuPhotonics absolute PL quantum yield measurement system equipped with axenon light source, a monochromator, a photonic multichannel analyzer,and an integrating sphere, and using PLQY measurement software(Hamamatsu Photonics, Ltd., Shizuoka, Japan), and the same experimentwas performed on each of Compounds 17, 24, 27 and 31. Results thereofare shown in Table 2.

TABLE 2 Compound No. PLQY 3 0.978 17 0.999 24 0.998 27 0.999 31 0.999 990.993 157 0.986 186 0.999 448 0.985

From Table 2, it was confirmed that Compounds 3, 17, 24, 27, 31, 99,157, 186 and 448 had high PLQY (in film).

Evaluation Example 2: Decay Time Measurement

A quartz substrate washed with chloroform and pure water was prepared,and then, a predetermined material shown in Table 3 wasvacuum-(co)deposited at a degree of vacuum of 10⁷ torr to prepare Films1 to 5 having a thickness of 50 nanometers (nm).

TABLE 3 Film name Compound used in film production Film 1 CBP:Compound 3(weight ratio of 9:1) Film 2 CBP:Compound 17 (weight ratio of 9:1) Film3 CBP:Compound 24 (weight ratio of 9:1) Film 4 CBP:Compound 27 (weightratio of 9:1) Film 5 CBP:Compound 31 (weight ratio of 9:1) Film 6CBP:Compound 99 (weight ratio of 9:1) Film 7 CBP:Compound 157 (weightratio of 9:1) Film 8 CBP:Compound 186 (weight ratio of 9:1) Film 9CBP:Compound 448 (weight ratio of 9:1)

Photoluminescence (PL) spectrum of each of Films 1 to 9 was measured byusing FluoTime 300, which is a TRPL measurement system manufactured byPicoQuant Inc. and PLS340 (excitation wavelength=340 nanometers,spectral width=20 nanometers), which is a pumping source of PicoQuantInc. at room temperature. Then, the main peak of each spectrum wasidentified, and the number of photons emitted at the wavelength ofphoton pulse (pulse width=500 picoseconds) applied by PLS340 to each ofFilms 1 to 9 was repeatedly measured based on time-correlated singlephoton counting (TCSPC) according to time, thereby obtaining a TRPLcurve sufficient for fitting. The obtained result was fitted with two ormore exponential decay functions to obtain T_(decay) (E_(x)), that is,decay time of each of Films 1 to 9 (decay time). Results obtainedtherefrom were shown in Table 4. A function for fitting is as shown inEquation 1, and from among T_(decay) values obtained from eachexponential decay function used for fitting, the largest T_(decay) wasobtained as T_(decay) (E_(x)). In this regard, the same measurement wasperformed during the same measurement time as that for obtaining TRPLcurve in the dark state (in which pumping signals entering a film areblocked) to obtain a baseline or a background signal curve for use as abaseline for fitting.

TABLE 4 Decay time Film name (μs) Film 1 (Compound 3) 2.340 Film 2(Compound 17) 2.081 Film 3 (Compound 24) 2.010 Film 4 (Compound 27)2.174 Film 5 (Compound 31) 2.002 Film 6 (Compound 99) 2.228 Film 7(Compound 157) 2.470 Film 8 (Compound 186) 2.323 Film 9 (Compound 448)2.371

From Table 4, it was confirmed that Compounds 3, 17, 24, 27, 31, 99,157, 186 and 448 had excellent decay time characteristics.

Example 1

An ITO glass substrate was cut to a size of 50 mm×50 mm×0.5 mm(mm=millimeter) and then, sonicated in acetone iso-propyl alcohol andpure water, each for 15 minutes, and then, washed by exposure to UVozone for 30 minutes.

Then, m-MTDATA was deposited on an ITO electrode (anode) of the glasssubstrate at a deposition speed of 1 Angstroms per second (A/sec) toform a hole injection layer having a thickness of 600 Angstroms (Å), andthen, α-NPD (NPB) was deposited on the hole injection layer at adeposition speed of 1 Å/sec to form a hole transport layer having athickness of 250 Å.

Compound 3 (dopant) and CBP (host) were co-deposited on the holetransport layer at a deposition speed of 0.1 Å/sec and a depositionspeed of 1 Å/sec, respectively, to form an emission layer having athickness of 400 Å.

BAlq was deposited on the emission layer at a deposition speed of 1Å/sec to form a hole blocking layer having a thickness of 50 Å, and Alq₃was deposited on the hole blocking layer to form an electron transportlayer having a thickness of 300 Å, and then, LiF was deposited on theelectron transport layer to form an electron injection layer having athickness of 10 Å, and then, Al was vacuum deposited on the electroninjection layer to form a second electrode (cathode) having a thicknessof 1,200 Å, thereby completing manufacturing of an organiclight-emitting device having a structure of ITO/m-MTDATA (600 Å)/α-NPD(250 Å)/CBP+Compound 3 (10%) (400 Å)/BAlq (50 Å)/Alq₃ (300 Å)/LiF (10Å)/Al (1,200 Å).

Examples 2 to 9 and Comparative Examples a to C

Organic light-emitting devices were manufactured in the same manner asin Example 1, except that in forming an emission layer, for use as adopant, corresponding compounds shown in Table 5 were used instead ofCompound 3.

Evaluation Example 3: Evaluation on Characteristics of OrganicLight-Emitting Devices

The driving voltage, the luminescence quantum efficiency, the roll-offratio, and the lifespan (T₉₅) of each of the organic light-emittingdevices manufactured according to Examples 1 to 9 and ComparativeExamples A to C were evaluated. Results thereof are shown in Table 5.This evaluation was performed using a current-voltage meter (Keithley2400) and a luminescence meter (Minolta Cs-1,000A), and the lifespan(T₉₅)(at 6000 nit) was evaluated by measuring the amount of time thatelapsed until luminance was reduced to 95% of the initial brightness of100%. The lifespan (T₉₅)(at 6000 nit) was represented as a relativevalue (%) in Table 5. The roll-off ratio was calculated by the followingequation:Roll off ratio={1−(efficiency (at 9,000 nit)/maximum luminescentefficiency)}×100%  Equation 20

TABLE 5 Luminescent Lifespan Dopant Driving quantum Roll-off (RelativeCompound Voltage Efficiency ratio value, %) No. No. (V) (%) (%) (T₉₅)Example 1 3 4.12 19.9 10 15.8% Example 2 17 4.08 23.2 9 20.1% Example 324 4.11 24.7 8 21.5% Example 4 27 3.85 23.3 9 32.4% Example 5 31 3.9722.8 8 23.0% Example 6 99 4.19 25.0 4 35.3% Example 7 157 3.97 26.5 738.3% Example 8 186 4.08 26.2 8 20.7% Example 9 448 3.86 26.5 7 34.9%Comparative A 4.54 17.8 11 4.2% Example A Comparative B 5.8 14.3 14 7.7%Example B Comparative C 5.7 10.2 12 3.0% Example C

From Table 5, it was confirmed that the organic light-emitting devicesof Example 1 to 9 have excellent driving voltage characteristics, highluminescence quantum efficiency, low roll-off ratio, and excellentlifespan characteristics compared to the organic light-emitting devicesof Comparative Examples A to CC

The organometallic compound according to embodiments has excellentelectric characteristics and thermal stability. Accordingly, an organiclight-emitting device including the organometallic compound may haveexcellent driving voltage, quantum efficiency, power efficiency, colorpurity, and lifespan characteristics. Such organometallic compounds haveexcellent phosphorescent luminescent characteristics, and thus, whenused, a diagnostic composition having a high diagnostic efficiency maybe provided.

It should be understood that embodiments described herein should beconsidered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

While one or more embodiments have been described with reference to theFIGURES, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present description asdefined by the following claims.

What is claimed is:
 1. An organometallic compound represented by Formula 1:

wherein, in Formula 1, M is beryllium (Be), magnesium (Mg), aluminum (Al), calcium (Ca), titanium (Ti), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), zirconium (Zr), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), rhenium (Re), platinum (Pt), or gold (Au), X₁ is a chemical bond, O, S, N(R′), P(R′), B(R′), C(R′)(R″), or Si(R′)(R″), and when X₁ is a chemical bond, Y₁ is directly bonded to M, X₂ to X₄ are each independently N or C, wherein two selected from X₂ to X₄ are each N and the other is C, a bond between X₁ or Y₁ and M is a covalent bond, one bond selected from a bond between X₂ and M, a bond between X₃ and M, and a bond between X₄ and M is a covalent bond, and the remaining two bonds are coordinate bonds, Y₁ and Y₃ to Y₅ are each independently C or N, among pairs of X₂ and Y₃, X₂ and Y₄, Y₄ and Y₅, X₅₁ and Y₃, and X₅₁ and Y₅, the components in each pair are linked via a chemical bond, ring CY₁ to ring CY₅ are each independently selected from a C₅-C₃₀ carbocyclic group and a C₁-C₃₀ heterocyclic group, and each of ring CY₁, ring CY₃, and ring CY₄ is not a benzimidazole group, a cyclometalated ring formed by ring CY₅, ring CY₂, ring CY₃, and M is a 6-membered ring, X₅₁ is selected from O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), C(═O), N, C(R₇), Si(R₇), and Ge(R₇), R₇ and R₈ are optionally linked via a single bond, a double bond, or a first linking group to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), T₁ and T₂ are each independently selected from a single bond, a double bond, *—N(R₉)—*, *—B(R₉)—*′, *—P(R₉)—*′, *—C(R₉)(R₁₀)—*′, *—Si(R₉)(R₁₀)—*′, *—Ge(R₉)(R₁₀)—*′, *—S—*′, *—Se—*′, *—O—*′, *—C(═O)—*′, *—S(═O)—*′, *—S(═O)₂—*′, *—C(R₉)═*′, *═C(R₉)—*′, *—C(R₉)═C(R₁₀)—*′, *—C(═S)—*′, or *—C≡C—*′, L₁ to L₄ and L₇ are each independently selected from a single bond, a substituted or unsubstituted C₅-C₃₀ carbocyclic group, and a substituted or unsubstituted C₁-C₃₀ heterocyclic group, b1 to b4 and b7 are each independently an integer from 1 to 5, R₁ to R₄, R₇ to R₁₀, R′ and R″ are each independently selected from hydrogen, deuterium, a deuterium-containing group, —F, —Cl, —Br, —I, —SF₅, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a substituted or unsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₇-C₆₀ alkylaryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstituted C₁-C₆₀ heteroarylthio group, a substituted or unsubstituted C₂-C₆₀ heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀ alkylheteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁)(Q₂), —Si(Q₃)(Q₄)(Q₅), —B(Q₆)(Q₇), and —P(═O)(Q₈)(Q₉), c1 to c4 and c7 are each independently an integer from 1 to 5, each of Z₁ to Z₄ is deuterium or a deuterium-containing group, a1 to a4 and n1 to n4 are each independently an integer from 0 to 20, i) when X₅₁ is O, S, C(═O), or N, the sum of n1 to n4 is 1 or more, ii) when X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)], C(R₇), Si(R₇), or Ge(R₇), a) R₇ is a deuterium-containing group; b) the sum of n1 to n4 is 1 or more; or c) R₇ is a deuterium-containing group and the sum of n1 to n4 is 1 or more, and iii) when X₅₁ is C(R₇)(R₈), Si(R₇)(R₈), or Ge(R₇)(R₈), a) at least one selected from R₇ and R₈ is a deuterium-containing group; b) the sum of n1 to n4 is 1 or more; or c) at least one selected from R₇ and R₈ is a deuterium-containing group and the sum of n1 to n4 is 1 or more, the deuterium-containing group is a first group substituted with at least one deuterium, and the first group is selected from a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀ cycloakenyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₇-C₆₀ alkylaryl group, a substituted or unsubstituted C₇-C₆₀ arylalkyl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstituted C₇-C₆₀ heteroarylalkyl group, a substituted or unsubstituted C₂-C₆₀ alkylheteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heterocyclic group, two of a plurality of neighboring groups R₁ are optionally linked to each other to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), two of a plurality of neighboring groups R₂ are optionally linked to each other to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R₁₀, two of a plurality of neighboring groups R₃ are optionally linked to each other to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), two of a plurality of neighboring groups R₄ are optionally linked to each other to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), two or more neighboring groups selected from R₁ to R₄, R₇ to R₁₀, R′, and R″ are optionally linked to form a C₅-C₃₀ carbocyclic group unsubstituted or substituted with at least one R_(10a) or a C₁-C₃₀ heterocyclic group unsubstituted or substituted with at least one R_(10a), R_(10a) has the same definition as R₁, at least one substituent of the substituted C₅-C₃₀ carbocyclic group, the substituted C₁-C₃₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group, the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, the substituted C₇-C₆₀ alkylaryl group, the substituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group, the substituted C₇-C₆₀ arylalkyl group, the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀ heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, the substituted C₂-C₆₀ heteroarylalkyl group, the substituted C₂-C₆₀ alkylheteroaryl group, the substituted monovalent non-aromatic condensed polycyclic group, and the substituted monovalent non-aromatic condensed heteropolycyclic group is selected from: deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₁₁)(Q₁₂), —Si(Q₁₃)(Q₁₄)(Q₁₅), —B(Q₁₆)(Q₁₇), and —P(═O)(Q₁₈)(Q₁₉); a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group; a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₇-C₆₀ alkylaryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic condensed polycyclic group, a monovalent non-aromatic condensed heteropolycyclic group, —N(Q₂₁)(Q₂₂), —Si(Q₂₃)(Q₂₄)(Q₂₅), —B(Q₂₆)(Q₂₇), and —P(═O)(Q₂₈)(Q₂₉); and —N(Q₃₁)(Q₃₂), —Si(Q₃₃)(Q₃₄)(Q₃₅), —B(Q₃₆)(Q₃₇), and —P(═O)(Q₃₈)(Q₃₉); wherein Q₁ to Q₉, Q₁₁ to Q₁₉, Q₂₁ to Q₂₉, and Q₃₁ to Q₃₉ are each independently selected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₆₀ alkyl group, a C₁-C₆₀ alkyl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryl group substituted with at least one selected from deuterium, a C₁-C₆₀ alkyl group, and a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₇-C₆₀ arylalkyl group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a C₂-C₆₀ heteroarylalkyl group, a C₂-C₆₀ alkylheteroaryl group, a monovalent non-aromatic condensed polycyclic group, and a monovalent non-aromatic condensed heteropolycyclic group.
 2. The organometallic compound of claim 1, wherein i) X₂ and X₄ are each N, X₃ is C, a bond between X₂ and M and a bond between X₄ and M are each a coordinate bond, and a bond between X₃ and M is a covalent bond, i) X₂ and X₃ are each N, X₄ is C, a bond between X₂ and M and a bond between X₃ and M are each a coordinate bond, and a bond between X₄ and M is a covalent bond, or iii) X₃ and X₄ are each N, X₂ is C, a bond between X₃ and M and a bond between X₄ and M are each a coordinate bond, and a bond between X₂ and M is a covalent bond.
 3. The organometallic compound of claim 1, wherein ring CY₁ to ring CY₄ are each independently selected from i) a first ring, ii) a second ring, iii) a condensed ring in which two or more first rings are condensed with each other, iv) a condensed ring in which two or more second rings are condensed with each other, and v) a condensed ring in which one or more first rings and one or more second rings are condensed with each other, the first ring is selected from a cyclopentane group, a cyclopentadiene group, a furan group, a thiophene group, a pyrrole group, a silole group, an indene group, a benzofuran group, a benzothiophene group, an indole group, a benzosilole group, an oxazole group, an isoxazole group, an oxadiazole group, an isozadiazole group, an oxatriazole group, an isoxatriazole group, a thiazole group, an isothiazole group, a thiadiazole group, an isothiadiazole group, a thiatriazole group, an isothiatriazole group, a pyrazole group, an imidazole group, a triazole group, a tetrazole group, an azasilole group, a diazasilole group, and a triazasilole group, the second ring is selected from an adamantane group, a norbornane group, a norbornene group, a cyclohexane group, a cyclohexene group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, and a triazine group, and each of ring CY₁ to ring CY₄ is not a benzimidazole group.
 4. The organometallic compound of claim 1, wherein ring CY₁ to ring CY₄ are each independently selected from a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, cyclopentadiene group, a 1,2,3,4-tetrahydronaphthalene group, a furan group, a thiophene group, a silole group, an indene group, a fluorene group, an indole group, a carbazole group, a benzofuran group, a dibenzofuran group, a benzothiophene group, a dibenzothiophene group, a benzosilole group, a dibenzosilole group, an azafluorene group, an azacarbazole group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzosilole group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a quinoxaline group, a quinazoline group, a phenanthroline group, a pyrrole group, a pyrazole group, an imidazole group, a triazole group, an oxazole group, an isooxazole group, a thiazole group, an isothiazole group, an oxadiazole group, a thiadiazole group, a 5,6,7,8-tetrahydroisoquinoline group, and a 5,6,7,8-tetrahydroquinoline group.
 5. The organometallic compound of claim 1, wherein i) Y₃ to Y₅ are each C, a bond between X₅₁ and Y₃ and a bond between X₅₁ and Y₅ are each a single bond, and X₅₁ is O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or C(═O), ii) Y₃ and Y₄ are each C, Y₅ is N, a bond between X₅₁ and Y₃ is a double bond, a bond between X₅₁ and Y₅ is a single bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), iii) Y₃ and Y₅ are each C, Y₄ is N, a bond between X₅₁ and Y₃ is a single bond, a bond between X₅₁ and Y₅ is a double bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), iv) Y₃ is N, Y₄ and Y₅ are each C, a bond between X₅₁ and Y₃ is a single bond, a bond between X₅₁ and Y₅ is a double bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇), or v) Y₃ to Y₅ are each C, a bond between X₅₁ and Y₃ is a double bond, a bond between X₅₁ and Y₅ is a single bond, and X₅₁ is N, C(R₇), Si(R₇), or Ge(R₇).
 6. The organometallic compound of claim 1, wherein the first group is selected from: a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group; and a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, and an imidazopyrimidinyl group, each substituted with at least one selected from —F, —Cl, —Br, —I, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthrenyl group, an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenyl group, a pyrrolyl group, a thiophenyl group, a furanyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolyl group, an isoxazolyl group, a pyridinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, an isoindolyl group, an indolyl group, an indazolyl group, a purinyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a quinazolinyl group, a cinnolinyl group, a carbazolyl group, a phenanthrolinyl group, a benzimidazolyl group, a benzofuranyl group, a benzothiophenyl group, an isobenzothiazolyl group, a benzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group, an oxadiazolyl group, a triazinyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a dibenzosilolyl group, a benzocarbazolyl group, a dibenzocarbazolyl group, an imidazopyridinyl group, an imidazopyrimidinyl group, and —Si(Q₃₃)(Q₃₄)(Q₃₅); wherein Q₃₃ to Q₃₅ are each independently selected from: —CH₃, —CD₃, —CD₂H, —CDH₂, —CH₂CH₃, —CH₂CD₃, —CH₂CD₂H, —CH₂CDH₂, —CHDCH₃, —CHDCD₂H, —CHDCDH₂, —CHDCD₃, —CD₂CH₃, —CD₂CD₃, —CD₂CD₂H, and —CD₂CDH₂; an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group; and an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a phenyl group, and a naphthyl group, each substituted with at least one selected from a C₁ to C₁₀ alkyl group, and a phenyl group.
 7. The organometallic compound of claim 1, wherein the first group is selected from a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, and a terphenyl group, each unsubstituted or substituted with at least one selected from —F, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, a cyano group, a C₁-C₁₀ alkyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cycloctyl group, an adamantanyl group, a norbornanyl group, a norbornenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, a bicyclo[1.1.1]pentyl group, a bicyclo[2.1.1]hexyl group, a bicyclo[2.2.1]heptyl group, a bicyclo[2.2.2]octyl group, a phenyl group, a (C₁-C₂₀ alkyl)phenyl group, a biphenyl group, and a terphenyl group.
 8. The organometallic compound of claim 1, wherein R₁ to R₄, R₇ to R₁₀, R′, and R″ are each independently selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF₅, —CH₃, —CD₃, —CD₂H, —CDH₂, —CF₃, —CF₂H, —CFH₂, —CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃, —CD₂-CD(CD₃)₂, —CD₂-CD₂(CD₃), —CD(CD₃)—C(CD₃)₃, —CD(CD₃)-CD(CD₃)₂, —CD(CD₃)-CD₂(CD₃), —C(CD₃)₂-C(CD₃)₃, —C(CD₃)₂-CD(CD₃)₂, —C(CD₃)₂-CD₂(CD₃), a group represented by Formula 9-1 to 9-19, a group represented by Formulae 10-1 to 10-232, a group represented by Formulae 11-1 to 11-41, and —Si(Q₁)(Q₂)(Q₃), Z₁ to Z₄ are each independently selected from deuterium, —CD₃, —CD₂H, —CDH₂, —CD₂(CD₃), —CD(CD₃)₂, —C(CD₃)₃, —CD₂-C(CD₃)₃, —CD₂-CD(CD₃)₂, —CD₂-CD₂(CD₃), —CD(CD₃)-C(CD₃)₃, —CD(CD₃)-CD(CD₃)₂, —CD(CD₃)-CD₂(CD₃), —C(CD₃)₂-C(CD₃)₃, —C(CD₃)₂-CD(CD₃)₂, —C(CD₃)₂-CD₂(CD₃), and a group represented by one of Formulae 9-14 to 9-19, 10-11, 10-12, and 11-1 to 11-41:

wherein, in Formulae 9-1 to 9-19, 10-1 to 10-232, and 11-1 to 11-41, * indicates a binding site to a neighboring atom, Ph is a phenyl group, and TMS is a trimethylsilyl group.
 9. The organometallic compound of claim 1, wherein the deuterium-containing group is selected from a group represented by one of Formulae 11-1 to 11-41:

wherein * in Formulae 11-1 to 11-41 indicates a binding site to a neighboring atom.
 10. The organometallic compound of claim 1, wherein satisfying at least one of Condition A to Condition D: Condition A n1 is 1, 2, 3 or 4; Condition B X₅₁ is N[(L₇)_(b7)-(R₇)_(c7)] and R₇ is a deuterium-containing group; Condition C n3 is 1, 2 or 3; Condition D n4 is 1, 2, 3 or
 4. 11. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY1-1 to CY1-40:

wherein, in Formula CY1-1 to CY1-40, Y₁, R₁, Z₂, and n1 are the same as described in claim 1, and n1 is an integer from 0 to 7, X₁₉ is C(R_(19a))(R_(19b)), N[(L₁₉)_(b19)-(R₁₉)_(c19)], O, S, or Si(R_(19a))(R_(19b)), L₁₉ is the same as described in connection with L₁ in claim 1, b19 and c19 are the same as described in connection with b1 and c1 in claim 1, R₁₁ to R₁₉, R_(19a), and R_(19b) are the same as described in connection with R₁ in claim 1, a12 is an integer from 0 to 2, a13 is an integer from 0 to 3, a14 is an integer from 0 to 4, a15 is an integer from 0 to 5, a16 is an integer from 0 to 6, a17 is an integer from 0 to 7, *′ indicates a binding site to X₁ or M in Formula 1, and * indicates a binding site to T₁ in Formula
 1. 12. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY2-1 to CY2-20:

wherein, in Formulae CY2-1 to CY2-20, X₂, R₂, Z₂, and n2 are the same as described in claim 1, and n2 is an integer from 0 to 3, X₅₁ in Formulae CY2-1 to CY2-4 is O, S, N-[(L₇)_(b7)-(R₇)_(c7)], C(R₇)(R₈), Si(R₇)(R₈), Ge(R₇)(R₈), or C(═O), X₅₁ in Formulae CY2-5 to CY2-20 is N, C(R₇), Si(R₇), or Ge(R₇), L₇, b7, R₇, and c7 are the same as described in connection with claim 1, a22 is an integer from 0 to 2, a23 is an integer from 0 to 3, * indicates a binding site to T₁ in Formula 1, *′ indicates a binding site to M in Formula 1, and *″ indicates a binding site to ring CY₃ in Formula
 1. 13. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY3-1 to CY3-12:

wherein, in Formulae CY3-1 to CY3-12, X₃, R₃, Z₃, and n3 are the same as described in connection with claim 1, and n3 is an integer from 0 to 5, X₃₉ is C(R_(39a))(R_(39b)), N[(L₃₉)_(b39)-(R₃₉)_(c39)], O, S, or Si(R_(39a))(R_(39b)), L₃₉ is the same as explained in connection with L₃ in claim 1, b39 and c39 are the same as described in connection with b3 and c3 in claim 1, respectively, R_(39a) and R_(39b) are the same as described in connection with R₃ in claim 1, a32 is an integer from 0 to 2, a33 is an integer from 0 to 3, a34 is an integer from 0 to 4, a35 is an integer from 0 to 5, * indicates a binding site to T₂ in Formula 1, *′ indicates a binding site to M in Formula 1, and *″ indicates a binding site to ring CY₂ in Formula
 1. 14. The organometallic compound of claim 1, wherein a moiety represented by

in Formula 1 is a group represented by one of Formulae CY4-1 to CY4-26:

wherein, in Formulae CY4-1 to CY4-26, X₄, R₄, Z₄, and n4 are the same as described in connection with claim 1, and n4 is an integer from 0 to 6, X₄₉ is C(R_(49a))(R_(49b)), N[(L₄₉)_(b49)-(R₄₉)_(c49)], O, S, or Si(R_(49a))(R_(49b)), L₄₉ is the same as described in connection with L₄ in claim 1, b49 and c49 are the same as described in connection with b4 and c4 in claim 1, respectively, R₄₁ to R₄₉, R_(49a), and R_(49b) are the same as described in connection with R₄ in claim 1, respectively, a42 is an integer from 0 to 2, a43 is an integer from 0 to 3, a44 is an integer from 0 to 4, a45 is an integer from 0 to 5, a46 is an integer from 0 to 6, * indicates a binding site to T₂ in Formula 1, and *′ indicates a binding site to M in Formula
 1. 15. An organic light-emitting device comprising: a first electrode; a second electrode; and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer comprises an emission layer and at least one organometallic compound of claim
 1. 16. The organic light-emitting device of claim 15, wherein the first electrode is an anode, the second electrode is a cathode, the organic layer further includes a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer or any combination thereof, and the electron transport region includes a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.
 17. The organic light-emitting device of claim 15, wherein the organometallic compound is included in the emission layer.
 18. The organic light-emitting device of claim 17, wherein the emission layer further includes a host and the amount of the host is greater than the amount of the organometallic compound.
 19. A diagnostic composition comprising at least one organometallic compound of claim
 1. 20. An organometallic compound, wherein the organometallic compound is one of Compounds 1 to 666 below: 